diff --git a/README.md b/README.md
index e1a3403..3fbb8bf 100644
--- a/README.md
+++ b/README.md
@@ -524,9 +524,9 @@ For documentation, see [pkg/cache/README.md](pkg/cache/README.md).
 
 #### Security
 
-Authentication and authorization framework with hooks integration.
+Authentication and authorization framework with hooks integration. Database-backed providers use PostgreSQL stored procedures by default, with a portable Direct mode (plain Go/SQL) for SQLite, MySQL, or Postgres without the procedures installed.
 
-For documentation, see [pkg/security/README.md](pkg/security/README.md).
+For documentation, see [pkg/security/README.md](pkg/security/README.md) (see "Direct Mode" for the SQLite/portable-SQL path).
 
 #### Middleware
 
diff --git a/pkg/security/README.md b/pkg/security/README.md
index 5471a3c..0fd0a69 100644
--- a/pkg/security/README.md
+++ b/pkg/security/README.md
@@ -11,7 +11,8 @@ Type-safe, composable security system for ResolveSpec with support for authentic
 - ✅ **No Global State** - Each handler has its own security configuration
 - ✅ **Testable** - Easy to mock and test
 - ✅ **Extensible** - Implement custom providers for your needs
-- ✅ **Stored Procedures** - All database operations use PostgreSQL stored procedures for security and maintainability
+- ✅ **Stored Procedures** - Database operations use PostgreSQL stored procedures where available, for security and maintainability
+- ✅ **Direct Mode** - Portable Go/SQL fallback for SQLite, MySQL, or Postgres without the stored procedures installed — no code changes required
 - ✅ **OAuth2 Authorization Server** - Built-in OAuth 2.1 + PKCE server (RFC 8414, 7591, 7009, 7662) with login form and external provider federation
 - ✅ **Password Reset** - Self-service password reset with secure token generation and session invalidation
 
@@ -51,6 +52,94 @@ Type-safe, composable security system for ResolveSpec with support for authentic
 
 See `database_schema.sql` for complete stored procedure definitions and examples.
 
+**Not on Postgres, or don't have the procedures installed?** See [Direct Mode](#direct-mode-portable-sql-without-stored-procedures) below — every provider that calls a `resolvespec_*` procedure also has a portable Go/SQL implementation that works on SQLite, MySQL, or plain Postgres.
+
+## Direct Mode (portable SQL without stored procedures)
+
+Every database-backed provider (`DatabaseAuthenticator`, `JWTAuthenticator`, `DatabaseTwoFactorProvider`, `DatabasePasskeyProvider`, the OAuth2 methods/server, `DatabaseKeyStore`) has two code paths:
+
+- **Procedure mode** — calls the configured `resolvespec_*` stored procedure (original behavior, Postgres-only).
+- **Direct mode** — reimplements the same logic in Go using plain parameterized SQL against configurable table names. Works on SQLite, MySQL, or a Postgres database where the procedures were never deployed.
+
+### QueryMode
+
+Selection is controlled per-provider by a `QueryMode`:
+
+```go
+type QueryMode int
+
+const (
+    ModeAuto      QueryMode = iota // default
+    ModeProcedure
+    ModeDirect
+)
+```
+
+- **`ModeAuto`** (default, zero value) — auto-detects per connection:
+  - SQLite/MySQL drivers → Direct mode, no probing.
+  - Postgres drivers (`lib/pq`, `pgx`) → probes `pg_proc` for the configured procedure name and uses it **only if it actually exists**; otherwise falls back to Direct mode. The result is cached per procedure name and reset on reconnect.
+  - Any other/unrecognized driver (including `sqlmock` test doubles) → defaults to Procedure mode, preserving existing behavior for callers that don't expose an identifiable driver type.
+- **`ModeProcedure`** — always calls the stored procedure, regardless of dialect.
+- **`ModeDirect`** — always uses the portable Go/SQL path, never the stored procedure.
+
+Set it via the provider's `Options` struct or `With...` chain method:
+
+```go
+auth := security.NewDatabaseAuthenticatorWithOptions(db, security.DatabaseAuthenticatorOptions{
+    QueryMode: security.ModeDirect, // force Direct mode, e.g. for SQLite
+})
+
+tfaProvider := security.NewDatabaseTwoFactorProvider(sqliteDB, nil).
+    WithQueryMode(security.ModeDirect)
+```
+
+On a real SQLite/MySQL connection you can usually leave `QueryMode` unset — `ModeAuto` detects the dialect and uses Direct mode automatically.
+
+### TableNames / KeyStoreTableNames
+
+Direct mode reads/writes plain tables instead of calling procedures, so table names are configurable the same way procedure names are (`SQLNames`):
+
+```go
+type TableNames struct {
+    Users                  string // default: "users"
+    UserSessions           string // default: "user_sessions"
+    TokenBlacklist         string // default: "token_blacklist"
+    UserTOTPBackupCodes    string // default: "user_totp_backup_codes"
+    UserPasskeyCredentials string // default: "user_passkey_credentials"
+    UserPasswordResets     string // default: "user_password_resets"
+    OAuthClients           string // default: "oauth_clients"
+    OAuthCodes             string // default: "oauth_codes"
+}
+
+type KeyStoreTableNames struct {
+    UserKeys string // default: "user_keys" — used by DatabaseKeyStore
+}
+```
+
+`DefaultTableNames()` / `MergeTableNames()` / `ValidateTableNames()` mirror `DefaultSQLNames()` / `MergeSQLNames()` / `ValidateSQLNames()`. Set custom names via the same `Options`/`With...` surface as `QueryMode`:
+
+```go
+auth := security.NewDatabaseAuthenticatorWithOptions(db, security.DatabaseAuthenticatorOptions{
+    TableNames: &security.TableNames{Users: "app_users"}, // only override what differs
+})
+```
+
+`oauth2_methods.go` and `oauth_server_db.go` are methods on `*DatabaseAuthenticator` and reuse its `TableNames`/`QueryMode`; there's no separate config for them.
+
+### Schema
+
+`database_schema_sqlite.sql` is the portable companion to `database_schema.sql` — plain `CREATE TABLE` statements only (no functions, no triggers, no `jsonb`/`bytea`/array types), covering every table Direct mode reads or writes. Use it to stand up a SQLite (or adapt for MySQL) database for Direct mode.
+
+### What's NOT covered
+
+`ColumnSecurityProvider`/`RowSecurityProvider` (`resolvespec_column_security` / `resolvespec_row_security`) query an external `core.secaccess`/`core.hub_link` schema this package doesn't own. Direct mode has no portable equivalent to fabricate for these and returns `security.ErrDirectModeUnsupported` — use `ConfigColumnSecurityProvider`/`ConfigRowSecurityProvider` instead when not running against Postgres with those procedures installed.
+
+### Behavioral notes
+
+- Direct mode matches Procedure mode's current behavior exactly, including its TODOs — e.g. passwords are compared as-is (the stored procedures don't verify bcrypt hashes yet either; see the TODO in `resolvespec_login`/`resolvespec_password_reset`).
+- Session tokens generated by Direct mode use the same `sess_<hex>_<unix-timestamp>` shape as the plpgsql procedures.
+- `bytea`/array/`jsonb` Postgres-only columns (passkey credentials, OAuth2 client scopes, keystore `meta`) are stored as base64/JSON-encoded `TEXT` in Direct mode — transparent to callers, since the Go-level API already deals in those same encodings.
+
 ## Quick Start
 
 ```go
diff --git a/pkg/security/database_schema_sqlite.sql b/pkg/security/database_schema_sqlite.sql
new file mode 100644
index 0000000..32ab3c6
--- /dev/null
+++ b/pkg/security/database_schema_sqlite.sql
@@ -0,0 +1,141 @@
+-- Portable schema for Direct-mode (non-stored-procedure) operation.
+-- Plain CREATE TABLE statements only, no functions/triggers, using types
+-- understood by SQLite (and portable to MySQL). Used by Direct-mode tests
+-- and as a reference for deployments without Postgres.
+
+CREATE TABLE IF NOT EXISTS users (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    username VARCHAR(255) NOT NULL UNIQUE,
+    email VARCHAR(255) NOT NULL UNIQUE,
+    password VARCHAR(255),
+    user_level INTEGER DEFAULT 0,
+    roles VARCHAR(500),
+    is_active BOOLEAN DEFAULT 1,
+    created_at TIMESTAMP,
+    updated_at TIMESTAMP,
+    last_login_at TIMESTAMP,
+    program_user_id INTEGER DEFAULT 0,
+    program_user_table VARCHAR(255) DEFAULT '',
+    remote_id VARCHAR(255),
+    auth_provider VARCHAR(50),
+    totp_secret VARCHAR(255),
+    totp_enabled BOOLEAN DEFAULT 0,
+    totp_enabled_at TIMESTAMP
+);
+
+CREATE TABLE IF NOT EXISTS user_sessions (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    session_token VARCHAR(500) NOT NULL UNIQUE,
+    user_id INTEGER NOT NULL,
+    expires_at TIMESTAMP NOT NULL,
+    created_at TIMESTAMP,
+    last_activity_at TIMESTAMP,
+    ip_address VARCHAR(45),
+    user_agent TEXT,
+    access_token TEXT,
+    refresh_token TEXT,
+    token_type VARCHAR(50) DEFAULT 'Bearer',
+    auth_provider VARCHAR(50)
+);
+
+CREATE INDEX IF NOT EXISTS idx_session_token ON user_sessions(session_token);
+CREATE INDEX IF NOT EXISTS idx_user_id ON user_sessions(user_id);
+CREATE INDEX IF NOT EXISTS idx_expires_at ON user_sessions(expires_at);
+CREATE INDEX IF NOT EXISTS idx_refresh_token ON user_sessions(refresh_token);
+
+CREATE TABLE IF NOT EXISTS token_blacklist (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    token VARCHAR(500) NOT NULL,
+    user_id INTEGER,
+    expires_at TIMESTAMP NOT NULL,
+    created_at TIMESTAMP
+);
+
+CREATE TABLE IF NOT EXISTS user_totp_backup_codes (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    user_id INTEGER NOT NULL,
+    code_hash VARCHAR(64) NOT NULL,
+    used BOOLEAN DEFAULT 0,
+    used_at TIMESTAMP,
+    created_at TIMESTAMP
+);
+
+CREATE INDEX IF NOT EXISTS idx_totp_user_id ON user_totp_backup_codes(user_id);
+CREATE INDEX IF NOT EXISTS idx_totp_code_hash ON user_totp_backup_codes(code_hash);
+
+CREATE TABLE IF NOT EXISTS user_passkey_credentials (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    user_id INTEGER NOT NULL,
+    credential_id TEXT NOT NULL UNIQUE, -- base64 text (Direct mode), not native bytea
+    public_key TEXT NOT NULL,           -- base64 text
+    attestation_type VARCHAR(50) DEFAULT 'none',
+    aaguid TEXT,                        -- base64 text
+    sign_count INTEGER DEFAULT 0,
+    clone_warning BOOLEAN DEFAULT 0,
+    transports TEXT,                    -- JSON-encoded []string
+    backup_eligible BOOLEAN DEFAULT 0,
+    backup_state BOOLEAN DEFAULT 0,
+    name VARCHAR(255),
+    created_at TIMESTAMP,
+    last_used_at TIMESTAMP
+);
+
+CREATE INDEX IF NOT EXISTS idx_passkey_user_id ON user_passkey_credentials(user_id);
+CREATE INDEX IF NOT EXISTS idx_passkey_credential_id ON user_passkey_credentials(credential_id);
+
+CREATE TABLE IF NOT EXISTS user_password_resets (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    user_id INTEGER NOT NULL,
+    token_hash VARCHAR(64) NOT NULL UNIQUE,
+    expires_at TIMESTAMP NOT NULL,
+    created_at TIMESTAMP,
+    used BOOLEAN DEFAULT 0,
+    used_at TIMESTAMP
+);
+
+CREATE TABLE IF NOT EXISTS oauth_clients (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    client_id VARCHAR(255) NOT NULL UNIQUE,
+    redirect_uris TEXT NOT NULL,   -- JSON-encoded []string
+    client_name VARCHAR(255),
+    grant_types TEXT,              -- JSON-encoded []string
+    allowed_scopes TEXT,           -- JSON-encoded []string
+    is_active BOOLEAN DEFAULT 1,
+    created_at TIMESTAMP
+);
+
+CREATE TABLE IF NOT EXISTS oauth_codes (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    code VARCHAR(255) NOT NULL UNIQUE,
+    client_id VARCHAR(255) NOT NULL,
+    redirect_uri TEXT NOT NULL,
+    client_state TEXT,
+    code_challenge VARCHAR(255) NOT NULL,
+    code_challenge_method VARCHAR(10) DEFAULT 'S256',
+    session_token TEXT NOT NULL,
+    refresh_token TEXT,
+    scopes TEXT,                   -- JSON-encoded []string
+    expires_at TIMESTAMP NOT NULL,
+    created_at TIMESTAMP
+);
+
+CREATE INDEX IF NOT EXISTS idx_oauth_codes_code ON oauth_codes(code);
+CREATE INDEX IF NOT EXISTS idx_oauth_codes_expires ON oauth_codes(expires_at);
+
+CREATE TABLE IF NOT EXISTS user_keys (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    user_id INTEGER NOT NULL,
+    key_type VARCHAR(50) NOT NULL,
+    key_hash VARCHAR(64) NOT NULL UNIQUE,
+    name VARCHAR(255) NOT NULL DEFAULT '',
+    scopes TEXT,                   -- JSON-encoded []string
+    meta TEXT,                     -- JSON-encoded map
+    expires_at TIMESTAMP,
+    created_at TIMESTAMP,
+    last_used_at TIMESTAMP,
+    is_active BOOLEAN DEFAULT 1
+);
+
+CREATE INDEX IF NOT EXISTS idx_user_keys_user_id  ON user_keys(user_id);
+CREATE INDEX IF NOT EXISTS idx_user_keys_key_hash ON user_keys(key_hash);
+CREATE INDEX IF NOT EXISTS idx_user_keys_key_type ON user_keys(key_type);
diff --git a/pkg/security/direct_mode_test.go b/pkg/security/direct_mode_test.go
new file mode 100644
index 0000000..8673aaa
--- /dev/null
+++ b/pkg/security/direct_mode_test.go
@@ -0,0 +1,467 @@
+package security
+
+import (
+	"context"
+	"database/sql"
+	"encoding/base64"
+	"net/http"
+	"os"
+	"path/filepath"
+	"testing"
+	"time"
+
+	_ "github.com/mattn/go-sqlite3"
+)
+
+func futureTime() time.Time {
+	return time.Now().Add(1 * time.Hour)
+}
+
+// newDirectTestDB opens a fresh in-memory SQLite database and applies the
+// portable Direct-mode schema (database_schema_sqlite.sql), giving every
+// Direct-mode test a real, isolated database to exercise end-to-end.
+func newDirectTestDB(t *testing.T) *sql.DB {
+	t.Helper()
+
+	db, err := sql.Open("sqlite3", "file::memory:?cache=shared")
+	if err != nil {
+		t.Fatalf("failed to open sqlite db: %v", err)
+	}
+	db.SetMaxOpenConns(1) // keep the shared in-memory db single-connection so state isn't lost
+	t.Cleanup(func() { _ = db.Close() })
+
+	schemaPath := filepath.Join("database_schema_sqlite.sql")
+	schema, err := os.ReadFile(schemaPath)
+	if err != nil {
+		t.Fatalf("failed to read schema: %v", err)
+	}
+	if _, err := db.Exec(string(schema)); err != nil {
+		t.Fatalf("failed to apply schema: %v", err)
+	}
+	return db
+}
+
+func authenticatedRequest(token string) *http.Request {
+	req, _ := http.NewRequest(http.MethodGet, "/", nil)
+	req.Header.Set("Authorization", "Bearer "+token)
+	return req
+}
+
+func TestDirectMode_RegisterThenLogin(t *testing.T) {
+	db := newDirectTestDB(t)
+	auth := NewDatabaseAuthenticatorWithOptions(db, DatabaseAuthenticatorOptions{QueryMode: ModeDirect})
+	ctx := context.Background()
+
+	regResp, err := auth.Register(ctx, RegisterRequest{
+		Username: "alice",
+		Password: "hunter2",
+		Email:    "alice@example.com",
+		Roles:    []string{"user", "admin"},
+		Claims:   map[string]any{"ip_address": "127.0.0.1", "user_agent": "test-agent"},
+	})
+	if err != nil {
+		t.Fatalf("Register() error = %v", err)
+	}
+	if regResp.Token == "" || regResp.User == nil {
+		t.Fatalf("Register() returned incomplete response: %+v", regResp)
+	}
+	if len(regResp.User.Roles) != 2 {
+		t.Errorf("expected 2 roles, got %v", regResp.User.Roles)
+	}
+
+	loginResp, err := auth.Login(ctx, LoginRequest{Username: "alice", Password: "hunter2"})
+	if err != nil {
+		t.Fatalf("Login() error = %v", err)
+	}
+	if loginResp.User.UserName != "alice" {
+		t.Errorf("Login() user = %q, want alice", loginResp.User.UserName)
+	}
+
+	// Duplicate registration should fail.
+	if _, err := auth.Register(ctx, RegisterRequest{Username: "alice", Password: "x", Email: "other@example.com"}); err == nil {
+		t.Error("expected duplicate username registration to fail")
+	}
+}
+
+func TestDirectMode_SessionLifecycle(t *testing.T) {
+	db := newDirectTestDB(t)
+	auth := NewDatabaseAuthenticatorWithOptions(db, DatabaseAuthenticatorOptions{QueryMode: ModeDirect})
+	ctx := context.Background()
+
+	loginResp, err := auth.Register(ctx, RegisterRequest{Username: "bob", Password: "p", Email: "bob@example.com"})
+	if err != nil {
+		t.Fatalf("Register() error = %v", err)
+	}
+
+	userCtx, err := auth.Authenticate(authenticatedRequest(loginResp.Token))
+	if err != nil {
+		t.Fatalf("Authenticate() error = %v", err)
+	}
+	if userCtx.UserName != "bob" {
+		t.Errorf("Authenticate() user = %q, want bob", userCtx.UserName)
+	}
+
+	refreshResp, err := auth.RefreshToken(ctx, loginResp.Token)
+	if err != nil {
+		t.Fatalf("RefreshToken() error = %v", err)
+	}
+	if refreshResp.Token == "" || refreshResp.Token == loginResp.Token {
+		t.Errorf("RefreshToken() should return a new token, got %q", refreshResp.Token)
+	}
+
+	if err := auth.Logout(ctx, LogoutRequest{Token: refreshResp.Token, UserID: refreshResp.User.UserID}); err != nil {
+		t.Fatalf("Logout() error = %v", err)
+	}
+
+	if _, err := auth.RefreshToken(ctx, refreshResp.Token); err == nil {
+		t.Error("expected RefreshToken() after logout to fail")
+	}
+}
+
+func TestDirectMode_PasswordReset(t *testing.T) {
+	db := newDirectTestDB(t)
+	auth := NewDatabaseAuthenticatorWithOptions(db, DatabaseAuthenticatorOptions{QueryMode: ModeDirect})
+	ctx := context.Background()
+
+	if _, err := auth.Register(ctx, RegisterRequest{Username: "carol", Password: "old", Email: "carol@example.com"}); err != nil {
+		t.Fatalf("Register() error = %v", err)
+	}
+
+	resetResp, err := auth.RequestPasswordReset(ctx, PasswordResetRequest{Email: "carol@example.com"})
+	if err != nil {
+		t.Fatalf("RequestPasswordReset() error = %v", err)
+	}
+	if resetResp.Token == "" {
+		t.Fatal("expected a non-empty reset token")
+	}
+
+	if err := auth.CompletePasswordReset(ctx, PasswordResetCompleteRequest{Token: resetResp.Token, NewPassword: "new"}); err != nil {
+		t.Fatalf("CompletePasswordReset() error = %v", err)
+	}
+
+	// Reusing the same token should now fail.
+	if err := auth.CompletePasswordReset(ctx, PasswordResetCompleteRequest{Token: resetResp.Token, NewPassword: "again"}); err == nil {
+		t.Error("expected reusing a consumed reset token to fail")
+	}
+}
+
+func TestDirectMode_JWTLoginAndLogout(t *testing.T) {
+	db := newDirectTestDB(t)
+	jwtAuth := NewJWTAuthenticator("secret", db).WithQueryMode(ModeDirect)
+	directAuth := NewDatabaseAuthenticatorWithOptions(db, DatabaseAuthenticatorOptions{QueryMode: ModeDirect})
+	ctx := context.Background()
+
+	if _, err := directAuth.Register(ctx, RegisterRequest{Username: "dave", Password: "p", Email: "dave@example.com"}); err != nil {
+		t.Fatalf("Register() error = %v", err)
+	}
+
+	resp, err := jwtAuth.Login(ctx, LoginRequest{Username: "dave", Password: "p"})
+	if err != nil {
+		t.Fatalf("JWTAuthenticator.Login() error = %v", err)
+	}
+	if resp.User.UserName != "dave" {
+		t.Errorf("JWT login user = %q, want dave", resp.User.UserName)
+	}
+
+	if err := jwtAuth.Logout(ctx, LogoutRequest{Token: resp.Token, UserID: resp.User.UserID}); err != nil {
+		t.Fatalf("JWTAuthenticator.Logout() error = %v", err)
+	}
+}
+
+func TestDirectMode_TOTPEnableAndValidateBackupCode(t *testing.T) {
+	db := newDirectTestDB(t)
+	auth := NewDatabaseAuthenticatorWithOptions(db, DatabaseAuthenticatorOptions{QueryMode: ModeDirect})
+	ctx := context.Background()
+
+	regResp, err := auth.Register(ctx, RegisterRequest{Username: "erin", Password: "p", Email: "erin@example.com"})
+	if err != nil {
+		t.Fatalf("Register() error = %v", err)
+	}
+	userID := regResp.User.UserID
+
+	totp := NewDatabaseTwoFactorProvider(db, nil).WithQueryMode(ModeDirect)
+
+	if err := totp.Enable2FA(userID, "SECRET123", []string{"code1", "code2"}); err != nil {
+		t.Fatalf("Enable2FA() error = %v", err)
+	}
+
+	enabled, err := totp.Get2FAStatus(userID)
+	if err != nil {
+		t.Fatalf("Get2FAStatus() error = %v", err)
+	}
+	if !enabled {
+		t.Error("expected 2FA to be enabled")
+	}
+
+	secret, err := totp.Get2FASecret(userID)
+	if err != nil {
+		t.Fatalf("Get2FASecret() error = %v", err)
+	}
+	if secret != "SECRET123" {
+		t.Errorf("Get2FASecret() = %q, want SECRET123", secret)
+	}
+
+	valid, err := totp.ValidateBackupCode(userID, "code1")
+	if err != nil {
+		t.Fatalf("ValidateBackupCode() error = %v", err)
+	}
+	if !valid {
+		t.Error("expected backup code to be valid")
+	}
+
+	// Reusing the same backup code should fail.
+	if _, err := totp.ValidateBackupCode(userID, "code1"); err == nil {
+		t.Error("expected reusing a consumed backup code to fail")
+	}
+
+	if err := totp.Disable2FA(userID); err != nil {
+		t.Fatalf("Disable2FA() error = %v", err)
+	}
+	enabled, err = totp.Get2FAStatus(userID)
+	if err != nil {
+		t.Fatalf("Get2FAStatus() error = %v", err)
+	}
+	if enabled {
+		t.Error("expected 2FA to be disabled")
+	}
+}
+
+func TestDirectMode_PasskeyStoreAndFetch(t *testing.T) {
+	db := newDirectTestDB(t)
+	auth := NewDatabaseAuthenticatorWithOptions(db, DatabaseAuthenticatorOptions{QueryMode: ModeDirect})
+	ctx := context.Background()
+
+	regResp, err := auth.Register(ctx, RegisterRequest{Username: "frank", Password: "p", Email: "frank@example.com"})
+	if err != nil {
+		t.Fatalf("Register() error = %v", err)
+	}
+	userID := regResp.User.UserID
+
+	passkeys := NewDatabasePasskeyProvider(db, DatabasePasskeyProviderOptions{
+		RPID: "example.com", RPName: "Example", RPOrigin: "https://example.com", QueryMode: ModeDirect,
+	})
+
+	cred, err := passkeys.CompleteRegistration(ctx, userID, PasskeyRegistrationResponse{
+		RawID: []byte("credential-1"),
+		Response: PasskeyAuthenticatorAttestationResponse{
+			AttestationObject: []byte("public-key-bytes"),
+		},
+		Transports: []string{"internal", "usb"},
+	}, nil)
+	if err != nil {
+		t.Fatalf("CompleteRegistration() error = %v", err)
+	}
+	if cred.UserID != userID {
+		t.Errorf("CompleteRegistration() UserID = %d, want %d", cred.UserID, userID)
+	}
+
+	creds, err := passkeys.GetCredentials(ctx, userID)
+	if err != nil {
+		t.Fatalf("GetCredentials() error = %v", err)
+	}
+	if len(creds) != 1 {
+		t.Fatalf("expected 1 credential, got %d", len(creds))
+	}
+	if string(creds[0].CredentialID) != "credential-1" {
+		t.Errorf("GetCredentials() CredentialID = %q, want credential-1", creds[0].CredentialID)
+	}
+	if len(creds[0].Transports) != 2 {
+		t.Errorf("expected 2 transports, got %v", creds[0].Transports)
+	}
+
+	credentialIDB64 := base64.StdEncoding.EncodeToString(creds[0].CredentialID)
+
+	if err := passkeys.UpdateCredentialName(ctx, userID, credentialIDB64, "My Phone"); err != nil {
+		t.Fatalf("UpdateCredentialName() error = %v", err)
+	}
+
+	updated, err := passkeys.GetCredentials(ctx, userID)
+	if err != nil {
+		t.Fatalf("GetCredentials() error = %v", err)
+	}
+	if updated[0].Name != "My Phone" {
+		t.Errorf("expected updated name 'My Phone', got %q", updated[0].Name)
+	}
+
+	if err := passkeys.DeleteCredential(ctx, userID, credentialIDB64); err != nil {
+		t.Fatalf("DeleteCredential() error = %v", err)
+	}
+	remaining, err := passkeys.GetCredentials(ctx, userID)
+	if err != nil {
+		t.Fatalf("GetCredentials() error = %v", err)
+	}
+	if len(remaining) != 0 {
+		t.Errorf("expected 0 credentials after delete, got %d", len(remaining))
+	}
+}
+
+func TestDirectMode_OAuthGetOrCreateUserAndSession(t *testing.T) {
+	db := newDirectTestDB(t)
+	auth := NewDatabaseAuthenticatorWithOptions(db, DatabaseAuthenticatorOptions{QueryMode: ModeDirect})
+	ctx := context.Background()
+
+	userCtx := &UserContext{UserName: "gina", Email: "gina@example.com", Roles: []string{"user"}}
+	userID, err := auth.oauth2GetOrCreateUser(ctx, userCtx, "google")
+	if err != nil {
+		t.Fatalf("oauth2GetOrCreateUser() error = %v", err)
+	}
+	if userID == 0 {
+		t.Fatal("expected non-zero user ID")
+	}
+
+	// Calling again with the same email should return the same user, not create a duplicate.
+	userID2, err := auth.oauth2GetOrCreateUser(ctx, userCtx, "google")
+	if err != nil {
+		t.Fatalf("oauth2GetOrCreateUser() second call error = %v", err)
+	}
+	if userID2 != userID {
+		t.Errorf("expected same user ID on repeat call, got %d and %d", userID, userID2)
+	}
+}
+
+func TestDirectMode_KeyStoreCreateAndValidate(t *testing.T) {
+	db := newDirectTestDB(t)
+	auth := NewDatabaseAuthenticatorWithOptions(db, DatabaseAuthenticatorOptions{QueryMode: ModeDirect})
+	ctx := context.Background()
+
+	regResp, err := auth.Register(ctx, RegisterRequest{Username: "henry", Password: "p", Email: "henry@example.com"})
+	if err != nil {
+		t.Fatalf("Register() error = %v", err)
+	}
+
+	ks := NewDatabaseKeyStore(db, DatabaseKeyStoreOptions{QueryMode: ModeDirect})
+
+	createResp, err := ks.CreateKey(ctx, CreateKeyRequest{
+		UserID:  regResp.User.UserID,
+		KeyType: KeyTypeGenericAPI,
+		Name:    "test key",
+		Scopes:  []string{"read", "write"},
+		Meta:    map[string]any{"note": "test"},
+	})
+	if err != nil {
+		t.Fatalf("CreateKey() error = %v", err)
+	}
+	if createResp.RawKey == "" {
+		t.Fatal("expected a non-empty raw key")
+	}
+
+	validated, err := ks.ValidateKey(ctx, createResp.RawKey, KeyTypeGenericAPI)
+	if err != nil {
+		t.Fatalf("ValidateKey() error = %v", err)
+	}
+	if validated.UserID != regResp.User.UserID {
+		t.Errorf("ValidateKey() UserID = %d, want %d", validated.UserID, regResp.User.UserID)
+	}
+	if len(validated.Scopes) != 2 {
+		t.Errorf("expected 2 scopes, got %v", validated.Scopes)
+	}
+
+	keys, err := ks.GetUserKeys(ctx, regResp.User.UserID, "")
+	if err != nil {
+		t.Fatalf("GetUserKeys() error = %v", err)
+	}
+	if len(keys) != 1 {
+		t.Fatalf("expected 1 key, got %d", len(keys))
+	}
+
+	if err := ks.DeleteKey(ctx, regResp.User.UserID, keys[0].ID); err != nil {
+		t.Fatalf("DeleteKey() error = %v", err)
+	}
+
+	remaining, err := ks.GetUserKeys(ctx, regResp.User.UserID, "")
+	if err != nil {
+		t.Fatalf("GetUserKeys() error = %v", err)
+	}
+	if len(remaining) != 0 {
+		t.Errorf("expected 0 keys after delete, got %d", len(remaining))
+	}
+}
+
+func TestDirectMode_OAuthServerClientAndCode(t *testing.T) {
+	db := newDirectTestDB(t)
+	auth := NewDatabaseAuthenticatorWithOptions(db, DatabaseAuthenticatorOptions{QueryMode: ModeDirect})
+	ctx := context.Background()
+
+	client := &OAuthServerClient{
+		ClientID:     "client-1",
+		RedirectURIs: []string{"https://app.example.com/callback"},
+		ClientName:   "Example App",
+	}
+	registered, err := auth.OAuthRegisterClient(ctx, client)
+	if err != nil {
+		t.Fatalf("OAuthRegisterClient() error = %v", err)
+	}
+	if len(registered.GrantTypes) != 1 || registered.GrantTypes[0] != "authorization_code" {
+		t.Errorf("expected default grant types, got %v", registered.GrantTypes)
+	}
+	if len(registered.AllowedScopes) != 3 {
+		t.Errorf("expected default allowed scopes, got %v", registered.AllowedScopes)
+	}
+
+	fetched, err := auth.OAuthGetClient(ctx, "client-1")
+	if err != nil {
+		t.Fatalf("OAuthGetClient() error = %v", err)
+	}
+	if fetched.ClientName != "Example App" {
+		t.Errorf("OAuthGetClient() ClientName = %q, want %q", fetched.ClientName, "Example App")
+	}
+	if len(fetched.RedirectURIs) != 1 || fetched.RedirectURIs[0] != "https://app.example.com/callback" {
+		t.Errorf("OAuthGetClient() RedirectURIs = %v", fetched.RedirectURIs)
+	}
+
+	regResp, err := auth.Register(ctx, RegisterRequest{Username: "ivan", Password: "p", Email: "ivan@example.com"})
+	if err != nil {
+		t.Fatalf("Register() error = %v", err)
+	}
+
+	if err := auth.OAuthSaveCode(ctx, &OAuthCode{
+		Code:          "auth-code-2",
+		ClientID:      "client-1",
+		RedirectURI:   "https://app.example.com/callback",
+		CodeChallenge: "challenge",
+		SessionToken:  regResp.Token,
+		Scopes:        []string{"openid", "profile"},
+		ExpiresAt:     futureTime(),
+	}); err != nil {
+		t.Fatalf("OAuthSaveCode() error = %v", err)
+	}
+
+	exchanged, err := auth.OAuthExchangeCode(ctx, "auth-code-2")
+	if err != nil {
+		t.Fatalf("OAuthExchangeCode() error = %v", err)
+	}
+	if exchanged.ClientID != "client-1" {
+		t.Errorf("OAuthExchangeCode() ClientID = %q, want client-1", exchanged.ClientID)
+	}
+	if len(exchanged.Scopes) != 2 {
+		t.Errorf("expected 2 scopes, got %v", exchanged.Scopes)
+	}
+
+	// Code should be single-use.
+	if _, err := auth.OAuthExchangeCode(ctx, "auth-code-2"); err == nil {
+		t.Error("expected re-exchanging a used code to fail")
+	}
+
+	info, err := auth.OAuthIntrospectToken(ctx, regResp.Token)
+	if err != nil {
+		t.Fatalf("OAuthIntrospectToken() error = %v", err)
+	}
+	if !info.Active {
+		t.Error("expected token to be active")
+	}
+	if info.Username != "ivan" {
+		t.Errorf("OAuthIntrospectToken() Username = %q, want ivan", info.Username)
+	}
+
+	if err := auth.OAuthRevokeToken(ctx, regResp.Token); err != nil {
+		t.Fatalf("OAuthRevokeToken() error = %v", err)
+	}
+
+	info, err = auth.OAuthIntrospectToken(ctx, regResp.Token)
+	if err != nil {
+		t.Fatalf("OAuthIntrospectToken() after revoke error = %v", err)
+	}
+	if info.Active {
+		t.Error("expected token to be inactive after revoke")
+	}
+}
diff --git a/pkg/security/keystore_database.go b/pkg/security/keystore_database.go
index 75e7eb1..70d250a 100644
--- a/pkg/security/keystore_database.go
+++ b/pkg/security/keystore_database.go
@@ -23,6 +23,10 @@ type DatabaseKeyStoreOptions struct {
 	CacheTTL time.Duration
 	// SQLNames provides custom procedure names. If nil, uses DefaultKeyStoreSQLNames().
 	SQLNames *KeyStoreSQLNames
+	// TableNames provides custom table names for Direct mode. If nil, uses DefaultKeyStoreTableNames().
+	TableNames *KeyStoreTableNames
+	// QueryMode selects stored-procedure vs Direct-mode SQL. Default (zero value) is ModeAuto.
+	QueryMode QueryMode
 	// DBFactory is called to obtain a fresh *sql.DB when the existing connection is closed.
 	// If nil, reconnection is disabled.
 	DBFactory func() (*sql.DB, error)
@@ -38,12 +42,15 @@ type DatabaseKeyStoreOptions struct {
 // cache TTL, a deleted key may continue to authenticate for up to CacheTTL
 // (default 2 minutes) if the cache entry cannot be invalidated.
 type DatabaseKeyStore struct {
-	db        *sql.DB
-	dbMu      sync.RWMutex
-	dbFactory func() (*sql.DB, error)
-	sqlNames  *KeyStoreSQLNames
-	cache     *cache.Cache
-	cacheTTL  time.Duration
+	db         *sql.DB
+	dbMu       sync.RWMutex
+	dbFactory  func() (*sql.DB, error)
+	sqlNames   *KeyStoreSQLNames
+	tableNames *KeyStoreTableNames
+	queryMode  QueryMode
+	capability *dbCapability
+	cache      *cache.Cache
+	cacheTTL   time.Duration
 }
 
 // NewDatabaseKeyStore creates a DatabaseKeyStore with optional configuration.
@@ -60,12 +67,16 @@ func NewDatabaseKeyStore(db *sql.DB, opts ...DatabaseKeyStoreOptions) *DatabaseK
 		c = cache.GetDefaultCache()
 	}
 	names := MergeKeyStoreSQLNames(DefaultKeyStoreSQLNames(), o.SQLNames)
+	tableNames := resolveKeyStoreTableNames(o.TableNames)
 	return &DatabaseKeyStore{
-		db:        db,
-		dbFactory: o.DBFactory,
-		sqlNames:  names,
-		cache:     c,
-		cacheTTL:  o.CacheTTL,
+		db:         db,
+		dbFactory:  o.DBFactory,
+		sqlNames:   names,
+		tableNames: tableNames,
+		queryMode:  o.QueryMode,
+		capability: newDBCapability(),
+		cache:      c,
+		cacheTTL:   o.CacheTTL,
 	}
 }
 
@@ -86,6 +97,9 @@ func (ks *DatabaseKeyStore) reconnectDB() error {
 	ks.dbMu.Lock()
 	ks.db = newDB
 	ks.dbMu.Unlock()
+	if ks.capability != nil {
+		ks.capability.reset()
+	}
 	return nil
 }
 
@@ -99,6 +113,14 @@ func (ks *DatabaseKeyStore) CreateKey(ctx context.Context, req CreateKeyRequest)
 	rawKey := base64.RawURLEncoding.EncodeToString(rawBytes)
 	hash := hashSHA256Hex(rawKey)
 
+	if !ks.capability.ShouldUseProcedure(ctx, ks.queryMode, ks.getDB(), ks.sqlNames.CreateKey) {
+		key, err := ks.createKeyDirect(ctx, req, hash)
+		if err != nil {
+			return nil, err
+		}
+		return &CreateKeyResponse{Key: *key, RawKey: rawKey}, nil
+	}
+
 	type createRequest struct {
 		UserID    int            `json:"user_id"`
 		KeyType   KeyType        `json:"key_type"`
@@ -145,6 +167,10 @@ func (ks *DatabaseKeyStore) CreateKey(ctx context.Context, req CreateKeyRequest)
 // GetUserKeys returns all active, non-expired keys for the given user.
 // Pass an empty KeyType to return all types.
 func (ks *DatabaseKeyStore) GetUserKeys(ctx context.Context, userID int, keyType KeyType) ([]UserKey, error) {
+	if !ks.capability.ShouldUseProcedure(ctx, ks.queryMode, ks.getDB(), ks.sqlNames.GetUserKeys) {
+		return ks.getUserKeysDirect(ctx, userID, keyType)
+	}
+
 	var success bool
 	var errorMsg sql.NullString
 	var keysJSON sql.NullString
@@ -173,6 +199,10 @@ func (ks *DatabaseKeyStore) GetUserKeys(ctx context.Context, userID int, keyType
 // The delete procedure returns the key_hash so no separate lookup is needed.
 // Note: cache invalidation is best-effort; a cached entry may persist for up to CacheTTL.
 func (ks *DatabaseKeyStore) DeleteKey(ctx context.Context, userID int, keyID int64) error {
+	if !ks.capability.ShouldUseProcedure(ctx, ks.queryMode, ks.getDB(), ks.sqlNames.DeleteKey) {
+		return ks.deleteKeyDirect(ctx, userID, keyID)
+	}
+
 	var success bool
 	var errorMsg sql.NullString
 	var keyHash sql.NullString
@@ -207,6 +237,17 @@ func (ks *DatabaseKeyStore) ValidateKey(ctx context.Context, rawKey string, keyT
 		}
 	}
 
+	if !ks.capability.ShouldUseProcedure(ctx, ks.queryMode, ks.getDB(), ks.sqlNames.ValidateKey) {
+		key, err := ks.validateKeyDirect(ctx, hash, keyType)
+		if err != nil {
+			return nil, err
+		}
+		if ks.cache != nil {
+			_ = ks.cache.Set(ctx, cacheKey, *key, ks.cacheTTL)
+		}
+		return key, nil
+	}
+
 	var success bool
 	var errorMsg sql.NullString
 	var keyJSON sql.NullString
diff --git a/pkg/security/keystore_database_direct.go b/pkg/security/keystore_database_direct.go
new file mode 100644
index 0000000..af444e7
--- /dev/null
+++ b/pkg/security/keystore_database_direct.go
@@ -0,0 +1,216 @@
+package security
+
+import (
+	"context"
+	"database/sql"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"time"
+)
+
+// Direct-mode implementations mirroring the resolvespec_keystore_* stored
+// procedures in keystore_schema.sql using plain SQL against
+// TableNames.UserKeys. meta/scopes are stored as JSON-encoded TEXT instead
+// of Postgres JSONB.
+
+func (ks *DatabaseKeyStore) createKeyDirect(ctx context.Context, req CreateKeyRequest, keyHash string) (*UserKey, error) {
+	scopesJSON, err := json.Marshal(req.Scopes)
+	if err != nil {
+		return nil, fmt.Errorf("failed to marshal scopes: %w", err)
+	}
+	var metaJSON []byte
+	if req.Meta != nil {
+		metaJSON, err = json.Marshal(req.Meta)
+		if err != nil {
+			return nil, fmt.Errorf("failed to marshal meta: %w", err)
+		}
+	}
+
+	now := time.Now()
+	var id int64
+	err = ks.runDBOpWithReconnect(func(db *sql.DB) error {
+		query := rewritePlaceholders(db, fmt.Sprintf(
+			`INSERT INTO %s (user_id, key_type, key_hash, name, scopes, meta, expires_at, created_at, is_active) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)`,
+			ks.tableNames.UserKeys))
+		res, err := db.ExecContext(ctx, query, req.UserID, string(req.KeyType), keyHash, req.Name, string(scopesJSON), nullableString(metaJSON), req.ExpiresAt, now, true)
+		if err != nil {
+			return err
+		}
+		id, err = res.LastInsertId()
+		return err
+	})
+	if err != nil {
+		return nil, fmt.Errorf("create key query failed: %w", err)
+	}
+
+	return &UserKey{
+		ID:        id,
+		UserID:    req.UserID,
+		KeyType:   req.KeyType,
+		KeyHash:   keyHash,
+		Name:      req.Name,
+		Scopes:    req.Scopes,
+		Meta:      req.Meta,
+		ExpiresAt: req.ExpiresAt,
+		CreatedAt: now,
+		IsActive:  true,
+	}, nil
+}
+
+func (ks *DatabaseKeyStore) runDBOpWithReconnect(run func(*sql.DB) error) error {
+	db := ks.getDB()
+	if db == nil {
+		return fmt.Errorf("database connection is nil")
+	}
+	err := run(db)
+	if isDBClosed(err) {
+		if reconnErr := ks.reconnectDB(); reconnErr == nil {
+			err = run(ks.getDB())
+		}
+	}
+	return err
+}
+
+func (ks *DatabaseKeyStore) getUserKeysDirect(ctx context.Context, userID int, keyType KeyType) ([]UserKey, error) {
+	keys := []UserKey{}
+	err := ks.runDBOpWithReconnect(func(db *sql.DB) error {
+		var query string
+		var args []any
+		if keyType == "" {
+			query = rewritePlaceholders(db, fmt.Sprintf(
+				`SELECT id, user_id, key_type, name, scopes, meta, expires_at, created_at, last_used_at, is_active
+				 FROM %s WHERE user_id = ? AND is_active = ? AND (expires_at IS NULL OR expires_at > ?)`, ks.tableNames.UserKeys))
+			args = []any{userID, true, time.Now()}
+		} else {
+			query = rewritePlaceholders(db, fmt.Sprintf(
+				`SELECT id, user_id, key_type, name, scopes, meta, expires_at, created_at, last_used_at, is_active
+				 FROM %s WHERE user_id = ? AND is_active = ? AND (expires_at IS NULL OR expires_at > ?) AND key_type = ?`, ks.tableNames.UserKeys))
+			args = []any{userID, true, time.Now(), string(keyType)}
+		}
+
+		rows, err := db.QueryContext(ctx, query, args...)
+		if err != nil {
+			return err
+		}
+		defer rows.Close()
+
+		for rows.Next() {
+			var k UserKey
+			var kt string
+			var scopesJSON, metaJSON sql.NullString
+			var expiresAt, lastUsedAt sql.NullTime
+			if err := rows.Scan(&k.ID, &k.UserID, &kt, &k.Name, &scopesJSON, &metaJSON, &expiresAt, &k.CreatedAt, &lastUsedAt, &k.IsActive); err != nil {
+				return err
+			}
+			k.KeyType = KeyType(kt)
+			if scopesJSON.Valid && scopesJSON.String != "" {
+				_ = json.Unmarshal([]byte(scopesJSON.String), &k.Scopes)
+			}
+			if metaJSON.Valid && metaJSON.String != "" {
+				_ = json.Unmarshal([]byte(metaJSON.String), &k.Meta)
+			}
+			if expiresAt.Valid {
+				t := expiresAt.Time
+				k.ExpiresAt = &t
+			}
+			if lastUsedAt.Valid {
+				t := lastUsedAt.Time
+				k.LastUsedAt = &t
+			}
+			keys = append(keys, k)
+		}
+		return rows.Err()
+	})
+	if err != nil {
+		return nil, fmt.Errorf("get user keys query failed: %w", err)
+	}
+	return keys, nil
+}
+
+func (ks *DatabaseKeyStore) deleteKeyDirect(ctx context.Context, userID int, keyID int64) error {
+	var keyHash string
+	err := ks.runDBOpWithReconnect(func(db *sql.DB) error {
+		selQuery := rewritePlaceholders(db, fmt.Sprintf(`SELECT key_hash FROM %s WHERE id = ? AND user_id = ? AND is_active = ?`, ks.tableNames.UserKeys))
+		if err := db.QueryRowContext(ctx, selQuery, keyID, userID, true).Scan(&keyHash); err != nil {
+			return err
+		}
+		updQuery := rewritePlaceholders(db, fmt.Sprintf(`UPDATE %s SET is_active = ? WHERE id = ? AND user_id = ? AND is_active = ?`, ks.tableNames.UserKeys))
+		_, err := db.ExecContext(ctx, updQuery, false, keyID, userID, true)
+		return err
+	})
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return errors.New("key not found or already deleted")
+		}
+		return fmt.Errorf("delete key query failed: %w", err)
+	}
+
+	if keyHash != "" && ks.cache != nil {
+		_ = ks.cache.Delete(ctx, keystoreCacheKey(keyHash))
+	}
+	return nil
+}
+
+func (ks *DatabaseKeyStore) validateKeyDirect(ctx context.Context, keyHash string, keyType KeyType) (*UserKey, error) {
+	var k UserKey
+	var kt string
+	var scopesJSON, metaJSON sql.NullString
+	var expiresAt, lastUsedAt sql.NullTime
+
+	err := ks.runDBOpWithReconnect(func(db *sql.DB) error {
+		var query string
+		var args []any
+		if keyType == "" {
+			query = rewritePlaceholders(db, fmt.Sprintf(
+				`SELECT id, user_id, key_type, name, scopes, meta, expires_at, created_at, is_active
+				 FROM %s WHERE key_hash = ? AND is_active = ? AND (expires_at IS NULL OR expires_at > ?)`, ks.tableNames.UserKeys))
+			args = []any{keyHash, true, time.Now()}
+		} else {
+			query = rewritePlaceholders(db, fmt.Sprintf(
+				`SELECT id, user_id, key_type, name, scopes, meta, expires_at, created_at, is_active
+				 FROM %s WHERE key_hash = ? AND is_active = ? AND (expires_at IS NULL OR expires_at > ?) AND key_type = ?`, ks.tableNames.UserKeys))
+			args = []any{keyHash, true, time.Now(), string(keyType)}
+		}
+
+		if err := db.QueryRowContext(ctx, query, args...).Scan(&k.ID, &k.UserID, &kt, &k.Name, &scopesJSON, &metaJSON, &expiresAt, &k.CreatedAt, &k.IsActive); err != nil {
+			return err
+		}
+
+		now := time.Now()
+		updQuery := rewritePlaceholders(db, fmt.Sprintf(`UPDATE %s SET last_used_at = ? WHERE id = ?`, ks.tableNames.UserKeys))
+		_, err := db.ExecContext(ctx, updQuery, now, k.ID)
+		return err
+	})
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return nil, errors.New("invalid or expired key")
+		}
+		return nil, fmt.Errorf("validate key query failed: %w", err)
+	}
+
+	k.KeyType = KeyType(kt)
+	k.KeyHash = keyHash
+	if scopesJSON.Valid && scopesJSON.String != "" {
+		_ = json.Unmarshal([]byte(scopesJSON.String), &k.Scopes)
+	}
+	if metaJSON.Valid && metaJSON.String != "" {
+		_ = json.Unmarshal([]byte(metaJSON.String), &k.Meta)
+	}
+	if expiresAt.Valid {
+		t := expiresAt.Time
+		k.ExpiresAt = &t
+	}
+	_ = lastUsedAt
+	now := time.Now()
+	k.LastUsedAt = &now
+
+	return &k, nil
+}
+
+func nullableString(b []byte) any {
+	if b == nil {
+		return nil
+	}
+	return string(b)
+}
diff --git a/pkg/security/keystore_table_names.go b/pkg/security/keystore_table_names.go
new file mode 100644
index 0000000..2ecc761
--- /dev/null
+++ b/pkg/security/keystore_table_names.go
@@ -0,0 +1,44 @@
+package security
+
+import "fmt"
+
+// KeyStoreTableNames holds the configurable table name used by DatabaseKeyStore
+// in Direct mode. Use DefaultKeyStoreTableNames() for defaults and
+// MergeKeyStoreTableNames() for partial overrides.
+type KeyStoreTableNames struct {
+	UserKeys string // default: "user_keys"
+}
+
+// DefaultKeyStoreTableNames returns a KeyStoreTableNames with default table names.
+func DefaultKeyStoreTableNames() *KeyStoreTableNames {
+	return &KeyStoreTableNames{
+		UserKeys: "user_keys",
+	}
+}
+
+// MergeKeyStoreTableNames returns a copy of base with any non-empty fields from override applied.
+// If override is nil, a copy of base is returned.
+func MergeKeyStoreTableNames(base, override *KeyStoreTableNames) *KeyStoreTableNames {
+	if override == nil {
+		copied := *base
+		return &copied
+	}
+	merged := *base
+	if override.UserKeys != "" {
+		merged.UserKeys = override.UserKeys
+	}
+	return &merged
+}
+
+// ValidateKeyStoreTableNames checks that all non-empty table names are valid SQL identifiers.
+func ValidateKeyStoreTableNames(names *KeyStoreTableNames) error {
+	if names.UserKeys != "" && !validSQLIdentifier.MatchString(names.UserKeys) {
+		return fmt.Errorf("KeyStoreTableNames.UserKeys contains invalid characters: %q", names.UserKeys)
+	}
+	return nil
+}
+
+// resolveKeyStoreTableNames merges an optional override with defaults.
+func resolveKeyStoreTableNames(override *KeyStoreTableNames) *KeyStoreTableNames {
+	return MergeKeyStoreTableNames(DefaultKeyStoreTableNames(), override)
+}
diff --git a/pkg/security/oauth2_methods.go b/pkg/security/oauth2_methods.go
index 79a58de..2ca859f 100644
--- a/pkg/security/oauth2_methods.go
+++ b/pkg/security/oauth2_methods.go
@@ -226,6 +226,10 @@ func (a *DatabaseAuthenticator) getOAuth2Provider(providerName string) (*OAuth2P
 
 // oauth2GetOrCreateUser finds or creates a user based on OAuth2 info using stored procedure
 func (a *DatabaseAuthenticator) oauth2GetOrCreateUser(ctx context.Context, userCtx *UserContext, providerName string) (int, error) {
+	if !a.capability.ShouldUseProcedure(ctx, a.queryMode, a.getDB(), a.sqlNames.OAuthGetOrCreateUser) {
+		return a.oauth2GetOrCreateUserDirect(ctx, userCtx, providerName)
+	}
+
 	userData := map[string]interface{}{
 		"username":      userCtx.UserName,
 		"email":         userCtx.Email,
@@ -269,6 +273,10 @@ func (a *DatabaseAuthenticator) oauth2GetOrCreateUser(ctx context.Context, userC
 
 // oauth2CreateSession creates a new OAuth2 session using stored procedure
 func (a *DatabaseAuthenticator) oauth2CreateSession(ctx context.Context, sessionToken string, userID int, token *oauth2.Token, expiresAt time.Time, providerName string) error {
+	if !a.capability.ShouldUseProcedure(ctx, a.queryMode, a.getDB(), a.sqlNames.OAuthCreateSession) {
+		return a.oauth2CreateSessionDirect(ctx, sessionToken, userID, token, expiresAt, providerName)
+	}
+
 	sessionData := map[string]interface{}{
 		"session_token": sessionToken,
 		"user_id":       userID,
@@ -381,35 +389,9 @@ func (a *DatabaseAuthenticator) OAuth2RefreshToken(ctx context.Context, refreshT
 	}
 
 	// Get session by refresh token from database
-	var success bool
-	var errMsg *string
-	var sessionData []byte
-
-	err = a.getDB().QueryRowContext(ctx, fmt.Sprintf(`
-		SELECT p_success, p_error, p_data::text
-		FROM %s($1)
-	`, a.sqlNames.OAuthGetRefreshToken), refreshToken).Scan(&success, &errMsg, &sessionData)
-
+	session, err := a.oauthGetByRefreshToken(ctx, refreshToken)
 	if err != nil {
-		return nil, fmt.Errorf("failed to get session by refresh token: %w", err)
-	}
-
-	if !success {
-		if errMsg != nil {
-			return nil, fmt.Errorf("%s", *errMsg)
-		}
-		return nil, fmt.Errorf("invalid or expired refresh token")
-	}
-
-	// Parse session data
-	var session struct {
-		UserID      int       `json:"user_id"`
-		AccessToken string    `json:"access_token"`
-		TokenType   string    `json:"token_type"`
-		Expiry      time.Time `json:"expiry"`
-	}
-	if err := json.Unmarshal(sessionData, &session); err != nil {
-		return nil, fmt.Errorf("failed to parse session data: %w", err)
+		return nil, err
 	}
 
 	// Create oauth2.Token from stored data
@@ -434,64 +416,14 @@ func (a *DatabaseAuthenticator) OAuth2RefreshToken(ctx context.Context, refreshT
 	}
 
 	// Update session in database with new tokens
-	updateData := map[string]interface{}{
-		"user_id":           session.UserID,
-		"old_refresh_token": refreshToken,
-		"new_session_token": newSessionToken,
-		"new_access_token":  newToken.AccessToken,
-		"new_refresh_token": newToken.RefreshToken,
-		"expires_at":        newToken.Expiry,
-	}
-
-	updateJSON, err := json.Marshal(updateData)
-	if err != nil {
-		return nil, fmt.Errorf("failed to marshal update data: %w", err)
-	}
-
-	var updateSuccess bool
-	var updateErrMsg *string
-
-	err = a.getDB().QueryRowContext(ctx, fmt.Sprintf(`
-		SELECT p_success, p_error
-		FROM %s($1::jsonb)
-	`, a.sqlNames.OAuthUpdateRefreshToken), updateJSON).Scan(&updateSuccess, &updateErrMsg)
-
-	if err != nil {
-		return nil, fmt.Errorf("failed to update session: %w", err)
-	}
-
-	if !updateSuccess {
-		if updateErrMsg != nil {
-			return nil, fmt.Errorf("%s", *updateErrMsg)
-		}
-		return nil, fmt.Errorf("failed to update session")
+	if err := a.oauthUpdateRefreshTokenRecord(ctx, session.UserID, refreshToken, newSessionToken, newToken.AccessToken, newToken.RefreshToken, newToken.Expiry); err != nil {
+		return nil, err
 	}
 
 	// Get user data
-	var userSuccess bool
-	var userErrMsg *string
-	var userData []byte
-
-	err = a.getDB().QueryRowContext(ctx, fmt.Sprintf(`
-		SELECT p_success, p_error, p_data::text
-		FROM %s($1)
-	`, a.sqlNames.OAuthGetUser), session.UserID).Scan(&userSuccess, &userErrMsg, &userData)
-
+	userCtx, err := a.oauthGetUserByID(ctx, session.UserID)
 	if err != nil {
-		return nil, fmt.Errorf("failed to get user data: %w", err)
-	}
-
-	if !userSuccess {
-		if userErrMsg != nil {
-			return nil, fmt.Errorf("%s", *userErrMsg)
-		}
-		return nil, fmt.Errorf("failed to get user data")
-	}
-
-	// Parse user context
-	var userCtx UserContext
-	if err := json.Unmarshal(userData, &userCtx); err != nil {
-		return nil, fmt.Errorf("failed to parse user context: %w", err)
+		return nil, err
 	}
 
 	userCtx.SessionID = newSessionToken
@@ -499,7 +431,7 @@ func (a *DatabaseAuthenticator) OAuth2RefreshToken(ctx context.Context, refreshT
 	return &LoginResponse{
 		Token:        newSessionToken,
 		RefreshToken: newToken.RefreshToken,
-		User:         &userCtx,
+		User:         userCtx,
 		ExpiresIn:    int64(time.Until(newToken.Expiry).Seconds()),
 	}, nil
 }
diff --git a/pkg/security/oauth2_methods_direct.go b/pkg/security/oauth2_methods_direct.go
new file mode 100644
index 0000000..abfc448
--- /dev/null
+++ b/pkg/security/oauth2_methods_direct.go
@@ -0,0 +1,242 @@
+package security
+
+import (
+	"context"
+	"database/sql"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"strings"
+	"time"
+
+	"golang.org/x/oauth2"
+)
+
+// oauthRefreshSession is the session data needed to refresh an OAuth2 token,
+// shared by both the stored-procedure and Direct-mode code paths.
+type oauthRefreshSession struct {
+	UserID      int       `json:"user_id"`
+	AccessToken string    `json:"access_token"`
+	TokenType   string    `json:"token_type"`
+	Expiry      time.Time `json:"expiry"`
+}
+
+// oauth2GetOrCreateUserDirect mirrors resolvespec_oauth_getorcreateuser.
+func (a *DatabaseAuthenticator) oauth2GetOrCreateUserDirect(ctx context.Context, userCtx *UserContext, providerName string) (int, error) {
+	rolesStr := strings.Join(userCtx.Roles, ",")
+	var userID int
+
+	err := a.runDBOpWithReconnect(func(db *sql.DB) error {
+		query := rewritePlaceholders(db, fmt.Sprintf(`SELECT id FROM %s WHERE email = ?`, a.tableNames.Users))
+		err := db.QueryRowContext(ctx, query, userCtx.Email).Scan(&userID)
+		if err == nil {
+			now := time.Now()
+			updQuery := rewritePlaceholders(db, fmt.Sprintf(
+				`UPDATE %s SET last_login_at = ?, updated_at = ?, remote_id = COALESCE(remote_id, ?), auth_provider = COALESCE(auth_provider, ?) WHERE id = ?`,
+				a.tableNames.Users))
+			_, err := db.ExecContext(ctx, updQuery, now, now, userCtx.RemoteID, providerName, userID)
+			return err
+		}
+		if !errors.Is(err, sql.ErrNoRows) {
+			return err
+		}
+
+		now := time.Now()
+		insQuery := rewritePlaceholders(db, fmt.Sprintf(
+			`INSERT INTO %s (username, email, password, user_level, roles, is_active, created_at, updated_at, last_login_at, remote_id, auth_provider) VALUES (?, ?, NULL, ?, ?, ?, ?, ?, ?, ?, ?)`,
+			a.tableNames.Users))
+		res, err := db.ExecContext(ctx, insQuery, userCtx.UserName, userCtx.Email, userCtx.UserLevel, rolesStr, true, now, now, now, userCtx.RemoteID, providerName)
+		if err != nil {
+			return err
+		}
+		id, err := res.LastInsertId()
+		if err != nil {
+			return err
+		}
+		userID = int(id)
+		return nil
+	})
+	if err != nil {
+		return 0, fmt.Errorf("failed to get or create user: %w", err)
+	}
+	return userID, nil
+}
+
+// oauth2CreateSessionDirect mirrors resolvespec_oauth_createsession (insert-or-update by session_token).
+func (a *DatabaseAuthenticator) oauth2CreateSessionDirect(ctx context.Context, sessionToken string, userID int, token *oauth2.Token, expiresAt time.Time, providerName string) error {
+	return a.runDBOpWithReconnect(func(db *sql.DB) error {
+		var exists int
+		checkQuery := rewritePlaceholders(db, fmt.Sprintf(`SELECT 1 FROM %s WHERE session_token = ?`, a.tableNames.UserSessions))
+		err := db.QueryRowContext(ctx, checkQuery, sessionToken).Scan(&exists)
+		now := time.Now()
+		if err == nil {
+			updQuery := rewritePlaceholders(db, fmt.Sprintf(
+				`UPDATE %s SET access_token = ?, refresh_token = ?, token_type = ?, expires_at = ?, last_activity_at = ? WHERE session_token = ?`,
+				a.tableNames.UserSessions))
+			_, err := db.ExecContext(ctx, updQuery, token.AccessToken, token.RefreshToken, token.TokenType, expiresAt, now, sessionToken)
+			return err
+		}
+		if !errors.Is(err, sql.ErrNoRows) {
+			return err
+		}
+
+		insQuery := rewritePlaceholders(db, fmt.Sprintf(
+			`INSERT INTO %s (session_token, user_id, expires_at, created_at, last_activity_at, access_token, refresh_token, token_type, auth_provider) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)`,
+			a.tableNames.UserSessions))
+		_, err = db.ExecContext(ctx, insQuery, sessionToken, userID, expiresAt, now, now, token.AccessToken, token.RefreshToken, token.TokenType, providerName)
+		return err
+	})
+}
+
+// oauthGetByRefreshToken retrieves the session for a refresh token, dispatching between
+// the resolvespec_oauth_getrefreshtoken stored procedure and Direct-mode SQL.
+func (a *DatabaseAuthenticator) oauthGetByRefreshToken(ctx context.Context, refreshToken string) (*oauthRefreshSession, error) {
+	if !a.capability.ShouldUseProcedure(ctx, a.queryMode, a.getDB(), a.sqlNames.OAuthGetRefreshToken) {
+		var session oauthRefreshSession
+		err := a.runDBOpWithReconnect(func(db *sql.DB) error {
+			query := rewritePlaceholders(db, fmt.Sprintf(
+				`SELECT user_id, access_token, token_type, expires_at FROM %s WHERE refresh_token = ? AND expires_at > ?`,
+				a.tableNames.UserSessions))
+			return db.QueryRowContext(ctx, query, refreshToken, time.Now()).Scan(&session.UserID, &session.AccessToken, &session.TokenType, &session.Expiry)
+		})
+		if err != nil {
+			if errors.Is(err, sql.ErrNoRows) {
+				return nil, fmt.Errorf("refresh token not found or expired")
+			}
+			return nil, fmt.Errorf("failed to get session by refresh token: %w", err)
+		}
+		return &session, nil
+	}
+
+	var success bool
+	var errMsg *string
+	var sessionData []byte
+
+	err := a.getDB().QueryRowContext(ctx, fmt.Sprintf(`
+		SELECT p_success, p_error, p_data::text
+		FROM %s($1)
+	`, a.sqlNames.OAuthGetRefreshToken), refreshToken).Scan(&success, &errMsg, &sessionData)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get session by refresh token: %w", err)
+	}
+	if !success {
+		if errMsg != nil {
+			return nil, fmt.Errorf("%s", *errMsg)
+		}
+		return nil, fmt.Errorf("invalid or expired refresh token")
+	}
+
+	var session oauthRefreshSession
+	if err := json.Unmarshal(sessionData, &session); err != nil {
+		return nil, fmt.Errorf("failed to parse session data: %w", err)
+	}
+	return &session, nil
+}
+
+// oauthUpdateRefreshTokenRecord updates a session with new tokens, dispatching between
+// the resolvespec_oauth_updaterefreshtoken stored procedure and Direct-mode SQL.
+func (a *DatabaseAuthenticator) oauthUpdateRefreshTokenRecord(ctx context.Context, userID int, oldRefreshToken, newSessionToken, newAccessToken, newRefreshToken string, expiresAt time.Time) error {
+	if !a.capability.ShouldUseProcedure(ctx, a.queryMode, a.getDB(), a.sqlNames.OAuthUpdateRefreshToken) {
+		var rows int64
+		err := a.runDBOpWithReconnect(func(db *sql.DB) error {
+			query := rewritePlaceholders(db, fmt.Sprintf(
+				`UPDATE %s SET session_token = ?, access_token = ?, refresh_token = ?, expires_at = ?, last_activity_at = ? WHERE user_id = ? AND refresh_token = ?`,
+				a.tableNames.UserSessions))
+			res, err := db.ExecContext(ctx, query, newSessionToken, newAccessToken, newRefreshToken, expiresAt, time.Now(), userID, oldRefreshToken)
+			if err != nil {
+				return err
+			}
+			rows, err = res.RowsAffected()
+			return err
+		})
+		if err != nil {
+			return fmt.Errorf("failed to update session: %w", err)
+		}
+		if rows == 0 {
+			return fmt.Errorf("session not found")
+		}
+		return nil
+	}
+
+	updateData := map[string]interface{}{
+		"user_id":           userID,
+		"old_refresh_token": oldRefreshToken,
+		"new_session_token": newSessionToken,
+		"new_access_token":  newAccessToken,
+		"new_refresh_token": newRefreshToken,
+		"expires_at":        expiresAt,
+	}
+	updateJSON, err := json.Marshal(updateData)
+	if err != nil {
+		return fmt.Errorf("failed to marshal update data: %w", err)
+	}
+
+	var updateSuccess bool
+	var updateErrMsg *string
+	err = a.getDB().QueryRowContext(ctx, fmt.Sprintf(`
+		SELECT p_success, p_error
+		FROM %s($1::jsonb)
+	`, a.sqlNames.OAuthUpdateRefreshToken), updateJSON).Scan(&updateSuccess, &updateErrMsg)
+	if err != nil {
+		return fmt.Errorf("failed to update session: %w", err)
+	}
+	if !updateSuccess {
+		if updateErrMsg != nil {
+			return fmt.Errorf("%s", *updateErrMsg)
+		}
+		return fmt.Errorf("failed to update session")
+	}
+	return nil
+}
+
+// oauthGetUserByID retrieves user data by ID, dispatching between the
+// resolvespec_oauth_getuser stored procedure and Direct-mode SQL.
+func (a *DatabaseAuthenticator) oauthGetUserByID(ctx context.Context, userID int) (*UserContext, error) {
+	if !a.capability.ShouldUseProcedure(ctx, a.queryMode, a.getDB(), a.sqlNames.OAuthGetUser) {
+		var username, email, roles, programUserTable sql.NullString
+		var userLevel, programUserID sql.NullInt64
+		err := a.runDBOpWithReconnect(func(db *sql.DB) error {
+			query := rewritePlaceholders(db, fmt.Sprintf(
+				`SELECT username, email, user_level, roles, program_user_id, program_user_table FROM %s WHERE id = ? AND is_active = ?`,
+				a.tableNames.Users))
+			return db.QueryRowContext(ctx, query, userID, true).Scan(&username, &email, &userLevel, &roles, &programUserID, &programUserTable)
+		})
+		if err != nil {
+			if errors.Is(err, sql.ErrNoRows) {
+				return nil, fmt.Errorf("user not found")
+			}
+			return nil, fmt.Errorf("failed to get user data: %w", err)
+		}
+		return &UserContext{
+			UserID:           userID,
+			UserName:         username.String,
+			Email:            email.String,
+			UserLevel:        int(userLevel.Int64),
+			Roles:            parseRoles(roles.String),
+			ProgramUserID:    int(programUserID.Int64),
+			ProgramUserTable: programUserTable.String,
+		}, nil
+	}
+
+	var userSuccess bool
+	var userErrMsg *string
+	var userData []byte
+	err := a.getDB().QueryRowContext(ctx, fmt.Sprintf(`
+		SELECT p_success, p_error, p_data::text
+		FROM %s($1)
+	`, a.sqlNames.OAuthGetUser), userID).Scan(&userSuccess, &userErrMsg, &userData)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get user data: %w", err)
+	}
+	if !userSuccess {
+		if userErrMsg != nil {
+			return nil, fmt.Errorf("%s", *userErrMsg)
+		}
+		return nil, fmt.Errorf("failed to get user data")
+	}
+	var userCtx UserContext
+	if err := json.Unmarshal(userData, &userCtx); err != nil {
+		return nil, fmt.Errorf("failed to parse user context: %w", err)
+	}
+	return &userCtx, nil
+}
diff --git a/pkg/security/oauth_server_db.go b/pkg/security/oauth_server_db.go
index 4f9a095..d0e208d 100644
--- a/pkg/security/oauth_server_db.go
+++ b/pkg/security/oauth_server_db.go
@@ -44,6 +44,10 @@ type OAuthTokenInfo struct {
 
 // OAuthRegisterClient persists an OAuth2 client registration.
 func (a *DatabaseAuthenticator) OAuthRegisterClient(ctx context.Context, client *OAuthServerClient) (*OAuthServerClient, error) {
+	if !a.capability.ShouldUseProcedure(ctx, a.queryMode, a.getDB(), a.sqlNames.OAuthRegisterClient) {
+		return a.oauthRegisterClientDirect(ctx, client)
+	}
+
 	input, err := json.Marshal(client)
 	if err != nil {
 		return nil, fmt.Errorf("failed to marshal client: %w", err)
@@ -76,6 +80,10 @@ func (a *DatabaseAuthenticator) OAuthRegisterClient(ctx context.Context, client
 
 // OAuthGetClient retrieves a registered client by ID.
 func (a *DatabaseAuthenticator) OAuthGetClient(ctx context.Context, clientID string) (*OAuthServerClient, error) {
+	if !a.capability.ShouldUseProcedure(ctx, a.queryMode, a.getDB(), a.sqlNames.OAuthGetClient) {
+		return a.oauthGetClientDirect(ctx, clientID)
+	}
+
 	var success bool
 	var errMsg *string
 	var data []byte
@@ -103,6 +111,10 @@ func (a *DatabaseAuthenticator) OAuthGetClient(ctx context.Context, clientID str
 
 // OAuthSaveCode persists an authorization code.
 func (a *DatabaseAuthenticator) OAuthSaveCode(ctx context.Context, code *OAuthCode) error {
+	if !a.capability.ShouldUseProcedure(ctx, a.queryMode, a.getDB(), a.sqlNames.OAuthSaveCode) {
+		return a.oauthSaveCodeDirect(ctx, code)
+	}
+
 	input, err := json.Marshal(code)
 	if err != nil {
 		return fmt.Errorf("failed to marshal code: %w", err)
@@ -129,6 +141,10 @@ func (a *DatabaseAuthenticator) OAuthSaveCode(ctx context.Context, code *OAuthCo
 
 // OAuthExchangeCode retrieves and deletes an authorization code (single use).
 func (a *DatabaseAuthenticator) OAuthExchangeCode(ctx context.Context, code string) (*OAuthCode, error) {
+	if !a.capability.ShouldUseProcedure(ctx, a.queryMode, a.getDB(), a.sqlNames.OAuthExchangeCode) {
+		return a.oauthExchangeCodeDirect(ctx, code)
+	}
+
 	var success bool
 	var errMsg *string
 	var data []byte
@@ -157,6 +173,10 @@ func (a *DatabaseAuthenticator) OAuthExchangeCode(ctx context.Context, code stri
 
 // OAuthIntrospectToken validates a token and returns its metadata (RFC 7662).
 func (a *DatabaseAuthenticator) OAuthIntrospectToken(ctx context.Context, token string) (*OAuthTokenInfo, error) {
+	if !a.capability.ShouldUseProcedure(ctx, a.queryMode, a.getDB(), a.sqlNames.OAuthIntrospect) {
+		return a.oauthIntrospectTokenDirect(ctx, token)
+	}
+
 	var success bool
 	var errMsg *string
 	var data []byte
@@ -184,6 +204,10 @@ func (a *DatabaseAuthenticator) OAuthIntrospectToken(ctx context.Context, token
 
 // OAuthRevokeToken revokes a token by deleting the session (RFC 7009).
 func (a *DatabaseAuthenticator) OAuthRevokeToken(ctx context.Context, token string) error {
+	if !a.capability.ShouldUseProcedure(ctx, a.queryMode, a.getDB(), a.sqlNames.OAuthRevoke) {
+		return a.oauthRevokeTokenDirect(ctx, token)
+	}
+
 	var success bool
 	var errMsg *string
 
diff --git a/pkg/security/oauth_server_db_direct.go b/pkg/security/oauth_server_db_direct.go
new file mode 100644
index 0000000..e0e162e
--- /dev/null
+++ b/pkg/security/oauth_server_db_direct.go
@@ -0,0 +1,188 @@
+package security
+
+import (
+	"context"
+	"database/sql"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"time"
+)
+
+// Direct-mode implementations mirroring the OAuth2 server stored procedures
+// (resolvespec_oauth_register_client, etc.) in database_schema.sql, using
+// plain SQL against TableNames.OAuthClients / TableNames.OAuthCodes.
+// Array columns (redirect_uris, grant_types, allowed_scopes, scopes) are
+// JSON-encoded TEXT instead of native Postgres arrays.
+
+func (a *DatabaseAuthenticator) oauthRegisterClientDirect(ctx context.Context, client *OAuthServerClient) (*OAuthServerClient, error) {
+	grantTypes := client.GrantTypes
+	if len(grantTypes) == 0 {
+		grantTypes = []string{"authorization_code"}
+	}
+	allowedScopes := client.AllowedScopes
+	if len(allowedScopes) == 0 {
+		allowedScopes = []string{"openid", "profile", "email"}
+	}
+
+	redirectURIsJSON, err := json.Marshal(client.RedirectURIs)
+	if err != nil {
+		return nil, fmt.Errorf("failed to marshal redirect_uris: %w", err)
+	}
+	grantTypesJSON, err := json.Marshal(grantTypes)
+	if err != nil {
+		return nil, fmt.Errorf("failed to marshal grant_types: %w", err)
+	}
+	allowedScopesJSON, err := json.Marshal(allowedScopes)
+	if err != nil {
+		return nil, fmt.Errorf("failed to marshal allowed_scopes: %w", err)
+	}
+
+	err = a.runDBOpWithReconnect(func(db *sql.DB) error {
+		query := rewritePlaceholders(db, fmt.Sprintf(
+			`INSERT INTO %s (client_id, redirect_uris, client_name, grant_types, allowed_scopes, is_active, created_at) VALUES (?, ?, ?, ?, ?, ?, ?)`,
+			a.tableNames.OAuthClients))
+		_, err := db.ExecContext(ctx, query, client.ClientID, string(redirectURIsJSON), client.ClientName, string(grantTypesJSON), string(allowedScopesJSON), true, time.Now())
+		return err
+	})
+	if err != nil {
+		return nil, fmt.Errorf("failed to register client: %w", err)
+	}
+
+	return &OAuthServerClient{
+		ClientID:      client.ClientID,
+		RedirectURIs:  client.RedirectURIs,
+		ClientName:    client.ClientName,
+		GrantTypes:    grantTypes,
+		AllowedScopes: allowedScopes,
+	}, nil
+}
+
+func (a *DatabaseAuthenticator) oauthGetClientDirect(ctx context.Context, clientID string) (*OAuthServerClient, error) {
+	var redirectURIsJSON, grantTypesJSON, allowedScopesJSON sql.NullString
+	var clientName sql.NullString
+
+	err := a.runDBOpWithReconnect(func(db *sql.DB) error {
+		query := rewritePlaceholders(db, fmt.Sprintf(
+			`SELECT redirect_uris, client_name, grant_types, allowed_scopes FROM %s WHERE client_id = ? AND is_active = ?`,
+			a.tableNames.OAuthClients))
+		return db.QueryRowContext(ctx, query, clientID, true).Scan(&redirectURIsJSON, &clientName, &grantTypesJSON, &allowedScopesJSON)
+	})
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return nil, fmt.Errorf("client not found")
+		}
+		return nil, fmt.Errorf("failed to get client: %w", err)
+	}
+
+	result := &OAuthServerClient{ClientID: clientID, ClientName: clientName.String}
+	if redirectURIsJSON.Valid {
+		_ = json.Unmarshal([]byte(redirectURIsJSON.String), &result.RedirectURIs)
+	}
+	if grantTypesJSON.Valid {
+		_ = json.Unmarshal([]byte(grantTypesJSON.String), &result.GrantTypes)
+	}
+	if allowedScopesJSON.Valid {
+		_ = json.Unmarshal([]byte(allowedScopesJSON.String), &result.AllowedScopes)
+	}
+	return result, nil
+}
+
+func (a *DatabaseAuthenticator) oauthSaveCodeDirect(ctx context.Context, code *OAuthCode) error {
+	scopesJSON, err := json.Marshal(code.Scopes)
+	if err != nil {
+		return fmt.Errorf("failed to marshal scopes: %w", err)
+	}
+	method := code.CodeChallengeMethod
+	if method == "" {
+		method = "S256"
+	}
+
+	return a.runDBOpWithReconnect(func(db *sql.DB) error {
+		query := rewritePlaceholders(db, fmt.Sprintf(
+			`INSERT INTO %s (code, client_id, redirect_uri, client_state, code_challenge, code_challenge_method, session_token, refresh_token, scopes, expires_at, created_at)
+			 VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`, a.tableNames.OAuthCodes))
+		_, err := db.ExecContext(ctx, query, code.Code, code.ClientID, code.RedirectURI, code.ClientState, code.CodeChallenge,
+			method, code.SessionToken, code.RefreshToken, string(scopesJSON), code.ExpiresAt, time.Now())
+		return err
+	})
+}
+
+func (a *DatabaseAuthenticator) oauthExchangeCodeDirect(ctx context.Context, code string) (*OAuthCode, error) {
+	var result OAuthCode
+	var clientState, refreshToken sql.NullString
+	var scopesJSON sql.NullString
+
+	err := a.runDBOpWithReconnect(func(db *sql.DB) error {
+		query := rewritePlaceholders(db, fmt.Sprintf(
+			`SELECT client_id, redirect_uri, client_state, code_challenge, code_challenge_method, session_token, refresh_token, scopes
+			 FROM %s WHERE code = ? AND expires_at > ?`, a.tableNames.OAuthCodes))
+		err := db.QueryRowContext(ctx, query, code, time.Now()).Scan(
+			&result.ClientID, &result.RedirectURI, &clientState, &result.CodeChallenge, &result.CodeChallengeMethod, &result.SessionToken, &refreshToken, &scopesJSON)
+		if err != nil {
+			return err
+		}
+		delQuery := rewritePlaceholders(db, fmt.Sprintf(`DELETE FROM %s WHERE code = ?`, a.tableNames.OAuthCodes))
+		_, err = db.ExecContext(ctx, delQuery, code)
+		return err
+	})
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return nil, fmt.Errorf("invalid or expired code")
+		}
+		return nil, fmt.Errorf("failed to exchange code: %w", err)
+	}
+
+	result.Code = code
+	result.ClientState = clientState.String
+	result.RefreshToken = refreshToken.String
+	if scopesJSON.Valid {
+		_ = json.Unmarshal([]byte(scopesJSON.String), &result.Scopes)
+	}
+	return &result, nil
+}
+
+func (a *DatabaseAuthenticator) oauthIntrospectTokenDirect(ctx context.Context, token string) (*OAuthTokenInfo, error) {
+	var info OAuthTokenInfo
+	var roles sql.NullString
+	var exp, iat sql.NullTime
+
+	err := a.runDBOpWithReconnect(func(db *sql.DB) error {
+		query := rewritePlaceholders(db, fmt.Sprintf(
+			`SELECT u.id, u.username, u.email, u.user_level, u.roles, s.expires_at, s.created_at
+			 FROM %s s JOIN %s u ON u.id = s.user_id
+			 WHERE s.session_token = ? AND s.expires_at > ? AND u.is_active = ?`,
+			a.tableNames.UserSessions, a.tableNames.Users))
+		var userID int
+		err := db.QueryRowContext(ctx, query, token, time.Now(), true).Scan(&userID, &info.Username, &info.Email, &info.UserLevel, &roles, &exp, &iat)
+		if err != nil {
+			return err
+		}
+		info.Sub = fmt.Sprintf("%d", userID)
+		return nil
+	})
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return &OAuthTokenInfo{Active: false}, nil
+		}
+		return nil, fmt.Errorf("failed to introspect token: %w", err)
+	}
+
+	info.Active = true
+	info.Roles = parseRoles(roles.String)
+	if exp.Valid {
+		info.Exp = exp.Time.Unix()
+	}
+	if iat.Valid {
+		info.Iat = iat.Time.Unix()
+	}
+	return &info, nil
+}
+
+func (a *DatabaseAuthenticator) oauthRevokeTokenDirect(ctx context.Context, token string) error {
+	return a.runDBOpWithReconnect(func(db *sql.DB) error {
+		query := rewritePlaceholders(db, fmt.Sprintf(`DELETE FROM %s WHERE session_token = ?`, a.tableNames.UserSessions))
+		_, err := db.ExecContext(ctx, query, token)
+		return err
+	})
+}
diff --git a/pkg/security/passkey_provider.go b/pkg/security/passkey_provider.go
index fb153c1..8b9bf05 100644
--- a/pkg/security/passkey_provider.go
+++ b/pkg/security/passkey_provider.go
@@ -14,14 +14,17 @@ import (
 // DatabasePasskeyProvider implements PasskeyProvider using database storage
 // Procedure names are configurable via SQLNames (see DefaultSQLNames for defaults)
 type DatabasePasskeyProvider struct {
-	db        *sql.DB
-	dbMu      sync.RWMutex
-	dbFactory func() (*sql.DB, error)
-	rpID      string // Relying Party ID (domain)
-	rpName    string // Relying Party display name
-	rpOrigin  string // Expected origin for WebAuthn
-	timeout   int64  // Timeout in milliseconds (default: 60000)
-	sqlNames  *SQLNames
+	db         *sql.DB
+	dbMu       sync.RWMutex
+	dbFactory  func() (*sql.DB, error)
+	rpID       string // Relying Party ID (domain)
+	rpName     string // Relying Party display name
+	rpOrigin   string // Expected origin for WebAuthn
+	timeout    int64  // Timeout in milliseconds (default: 60000)
+	sqlNames   *SQLNames
+	tableNames *TableNames
+	queryMode  QueryMode
+	capability *dbCapability
 }
 
 // DatabasePasskeyProviderOptions configures the passkey provider
@@ -36,6 +39,10 @@ type DatabasePasskeyProviderOptions struct {
 	Timeout int64
 	// SQLNames provides custom SQL procedure/function names. If nil, uses DefaultSQLNames().
 	SQLNames *SQLNames
+	// TableNames provides custom table names for Direct mode. If nil, uses DefaultTableNames().
+	TableNames *TableNames
+	// QueryMode selects stored-procedure vs Direct-mode SQL. Default (zero value) is ModeAuto.
+	QueryMode QueryMode
 	// DBFactory is called to obtain a fresh *sql.DB when the existing connection is closed.
 	// If nil, reconnection is disabled.
 	DBFactory func() (*sql.DB, error)
@@ -48,15 +55,19 @@ func NewDatabasePasskeyProvider(db *sql.DB, opts DatabasePasskeyProviderOptions)
 	}
 
 	sqlNames := MergeSQLNames(DefaultSQLNames(), opts.SQLNames)
+	tableNames := resolveTableNames(opts.TableNames)
 
 	return &DatabasePasskeyProvider{
-		db:        db,
-		dbFactory: opts.DBFactory,
-		rpID:      opts.RPID,
-		rpName:    opts.RPName,
-		rpOrigin:  opts.RPOrigin,
-		timeout:   opts.Timeout,
-		sqlNames:  sqlNames,
+		db:         db,
+		dbFactory:  opts.DBFactory,
+		rpID:       opts.RPID,
+		rpName:     opts.RPName,
+		rpOrigin:   opts.RPOrigin,
+		timeout:    opts.Timeout,
+		sqlNames:   sqlNames,
+		tableNames: tableNames,
+		queryMode:  opts.QueryMode,
+		capability: newDBCapability(),
 	}
 }
 
@@ -77,9 +88,26 @@ func (p *DatabasePasskeyProvider) reconnectDB() error {
 	p.dbMu.Lock()
 	p.db = newDB
 	p.dbMu.Unlock()
+	if p.capability != nil {
+		p.capability.reset()
+	}
 	return nil
 }
 
+func (p *DatabasePasskeyProvider) runDBOpWithReconnect(run func(*sql.DB) error) error {
+	db := p.getDB()
+	if db == nil {
+		return fmt.Errorf("database connection is nil")
+	}
+	err := run(db)
+	if isDBClosed(err) {
+		if reconnErr := p.reconnectDB(); reconnErr == nil {
+			err = run(p.getDB())
+		}
+	}
+	return err
+}
+
 // BeginRegistration creates registration options for a new passkey
 func (p *DatabasePasskeyProvider) BeginRegistration(ctx context.Context, userID int, username, displayName string) (*PasskeyRegistrationOptions, error) {
 	// Generate challenge
@@ -145,10 +173,40 @@ func (p *DatabasePasskeyProvider) CompleteRegistration(ctx context.Context, user
 	// For now, this is a placeholder that stores the credential data
 	// In production, you MUST use a proper WebAuthn library
 
+	credIDB64 := base64.StdEncoding.EncodeToString(response.RawID)
+	pubKeyB64 := base64.StdEncoding.EncodeToString(response.Response.AttestationObject)
+
+	if !p.capability.ShouldUseProcedure(ctx, p.queryMode, p.getDB(), p.sqlNames.PasskeyStoreCredential) {
+		credentialID, err := p.storeCredentialDirect(ctx, storeCredentialParams{
+			UserID:          userID,
+			CredentialID:    credIDB64,
+			PublicKey:       pubKeyB64,
+			AttestationType: "none",
+			SignCount:       0,
+			Transports:      response.Transports,
+			BackupEligible:  false,
+			BackupState:     false,
+			Name:            "Passkey",
+		})
+		if err != nil {
+			return nil, err
+		}
+		return &PasskeyCredential{
+			ID:              fmt.Sprintf("%d", credentialID),
+			UserID:          userID,
+			CredentialID:    response.RawID,
+			PublicKey:       response.Response.AttestationObject,
+			AttestationType: "none",
+			Transports:      response.Transports,
+			CreatedAt:       time.Now(),
+			LastUsedAt:      time.Now(),
+		}, nil
+	}
+
 	credData := map[string]any{
 		"user_id":          userID,
-		"credential_id":    base64.StdEncoding.EncodeToString(response.RawID),
-		"public_key":       base64.StdEncoding.EncodeToString(response.Response.AttestationObject),
+		"credential_id":    credIDB64,
+		"public_key":       pubKeyB64,
 		"attestation_type": "none",
 		"sign_count":       0,
 		"transports":       response.Transports,
@@ -202,31 +260,39 @@ func (p *DatabasePasskeyProvider) BeginAuthentication(ctx context.Context, usern
 	// If username is provided, get user's credentials
 	var allowCredentials []PasskeyCredentialDescriptor
 	if username != "" {
-		var success bool
-		var errorMsg sql.NullString
-		var userID sql.NullInt64
-		var credentialsJSON sql.NullString
-
-		query := fmt.Sprintf(`SELECT p_success, p_error, p_user_id, p_credentials::text FROM %s($1)`, p.sqlNames.PasskeyGetCredsByUsername)
-		err := p.getDB().QueryRowContext(ctx, query, username).Scan(&success, &errorMsg, &userID, &credentialsJSON)
-		if err != nil {
-			return nil, fmt.Errorf("failed to get credentials: %w", err)
-		}
-
-		if !success {
-			if errorMsg.Valid {
-				return nil, fmt.Errorf("%s", errorMsg.String)
-			}
-			return nil, fmt.Errorf("failed to get credentials")
-		}
-
-		// Parse credentials
 		var creds []struct {
 			ID         string   `json:"credential_id"`
 			Transports []string `json:"transports"`
 		}
-		if err := json.Unmarshal([]byte(credentialsJSON.String), &creds); err != nil {
-			return nil, fmt.Errorf("failed to parse credentials: %w", err)
+
+		if !p.capability.ShouldUseProcedure(ctx, p.queryMode, p.getDB(), p.sqlNames.PasskeyGetCredsByUsername) {
+			_, directCreds, err := p.getCredsByUsernameDirect(ctx, username)
+			if err != nil {
+				return nil, err
+			}
+			creds = directCreds
+		} else {
+			var success bool
+			var errorMsg sql.NullString
+			var userID sql.NullInt64
+			var credentialsJSON sql.NullString
+
+			query := fmt.Sprintf(`SELECT p_success, p_error, p_user_id, p_credentials::text FROM %s($1)`, p.sqlNames.PasskeyGetCredsByUsername)
+			err := p.getDB().QueryRowContext(ctx, query, username).Scan(&success, &errorMsg, &userID, &credentialsJSON)
+			if err != nil {
+				return nil, fmt.Errorf("failed to get credentials: %w", err)
+			}
+
+			if !success {
+				if errorMsg.Valid {
+					return nil, fmt.Errorf("%s", errorMsg.String)
+				}
+				return nil, fmt.Errorf("failed to get credentials")
+			}
+
+			if err := json.Unmarshal([]byte(credentialsJSON.String), &creds); err != nil {
+				return nil, fmt.Errorf("failed to parse credentials: %w", err)
+			}
 		}
 
 		allowCredentials = make([]PasskeyCredentialDescriptor, 0, len(creds))
@@ -262,6 +328,24 @@ func (p *DatabasePasskeyProvider) CompleteAuthentication(ctx context.Context, re
 	// 3. Verify signature using stored public key
 	// 4. Update sign counter and check for cloning
 
+	credIDB64 := base64.StdEncoding.EncodeToString(response.RawID)
+
+	if !p.capability.ShouldUseProcedure(ctx, p.queryMode, p.getDB(), p.sqlNames.PasskeyGetCredential) {
+		userID, signCount, err := p.getCredentialDirect(ctx, credIDB64)
+		if err != nil {
+			return 0, err
+		}
+		newCounter := signCount + 1
+		cloneWarning, err := p.updateCounterDirect(ctx, credIDB64, newCounter)
+		if err != nil {
+			return 0, fmt.Errorf("failed to update counter: %w", err)
+		}
+		if cloneWarning {
+			return 0, fmt.Errorf("credential cloning detected")
+		}
+		return userID, nil
+	}
+
 	// Get credential from database
 	var success bool
 	var errorMsg sql.NullString
@@ -321,6 +405,10 @@ func (p *DatabasePasskeyProvider) CompleteAuthentication(ctx context.Context, re
 
 // GetCredentials returns all passkey credentials for a user
 func (p *DatabasePasskeyProvider) GetCredentials(ctx context.Context, userID int) ([]PasskeyCredential, error) {
+	if !p.capability.ShouldUseProcedure(ctx, p.queryMode, p.getDB(), p.sqlNames.PasskeyGetUserCredentials) {
+		return p.getUserCredentialsDirect(ctx, userID)
+	}
+
 	var success bool
 	var errorMsg sql.NullString
 	var credentialsJSON sql.NullString
@@ -401,6 +489,10 @@ func (p *DatabasePasskeyProvider) DeleteCredential(ctx context.Context, userID i
 		return fmt.Errorf("invalid credential ID: %w", err)
 	}
 
+	if !p.capability.ShouldUseProcedure(ctx, p.queryMode, p.getDB(), p.sqlNames.PasskeyDeleteCredential) {
+		return p.deleteCredentialDirect(ctx, userID, credentialID)
+	}
+
 	var success bool
 	var errorMsg sql.NullString
 
@@ -427,6 +519,10 @@ func (p *DatabasePasskeyProvider) UpdateCredentialName(ctx context.Context, user
 		return fmt.Errorf("invalid credential ID: %w", err)
 	}
 
+	if !p.capability.ShouldUseProcedure(ctx, p.queryMode, p.getDB(), p.sqlNames.PasskeyUpdateName) {
+		return p.updateNameDirect(ctx, userID, credentialID, name)
+	}
+
 	var success bool
 	var errorMsg sql.NullString
 
diff --git a/pkg/security/passkey_provider_direct.go b/pkg/security/passkey_provider_direct.go
new file mode 100644
index 0000000..f2b1dd0
--- /dev/null
+++ b/pkg/security/passkey_provider_direct.go
@@ -0,0 +1,261 @@
+package security
+
+import (
+	"context"
+	"database/sql"
+	"encoding/base64"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"time"
+)
+
+// Direct-mode implementations mirroring the resolvespec_passkey_* stored
+// procedures in database_schema.sql using plain SQL against TableNames.
+// credential_id/public_key/aaguid are stored as base64 TEXT (not native
+// bytea) and transports as JSON-encoded TEXT, so the same schema works on
+// SQLite, MySQL, and Postgres.
+
+type storeCredentialParams struct {
+	UserID          int
+	CredentialID    string // base64
+	PublicKey       string // base64
+	AttestationType string
+	SignCount       int
+	Transports      []string
+	BackupEligible  bool
+	BackupState     bool
+	Name            string
+}
+
+func (p *DatabasePasskeyProvider) storeCredentialDirect(ctx context.Context, params storeCredentialParams) (int64, error) {
+	transportsJSON, err := json.Marshal(params.Transports)
+	if err != nil {
+		return 0, fmt.Errorf("failed to marshal transports: %w", err)
+	}
+
+	var credentialID int64
+	err = p.runDBOpWithReconnect(func(db *sql.DB) error {
+		var exists int
+		checkQuery := rewritePlaceholders(db, fmt.Sprintf(`SELECT 1 FROM %s WHERE credential_id = ?`, p.tableNames.UserPasskeyCredentials))
+		if err := db.QueryRowContext(ctx, checkQuery, params.CredentialID).Scan(&exists); err == nil {
+			return fmt.Errorf("Credential already exists")
+		} else if !errors.Is(err, sql.ErrNoRows) {
+			return err
+		}
+
+		var userExists int
+		userCheckQuery := rewritePlaceholders(db, fmt.Sprintf(`SELECT 1 FROM %s WHERE id = ?`, p.tableNames.Users))
+		if err := db.QueryRowContext(ctx, userCheckQuery, params.UserID).Scan(&userExists); err != nil {
+			if errors.Is(err, sql.ErrNoRows) {
+				return fmt.Errorf("User not found")
+			}
+			return err
+		}
+
+		now := time.Now()
+		insertQuery := rewritePlaceholders(db, fmt.Sprintf(
+			`INSERT INTO %s (user_id, credential_id, public_key, attestation_type, aaguid, sign_count, transports, backup_eligible, backup_state, name, created_at, last_used_at)
+			 VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`, p.tableNames.UserPasskeyCredentials))
+		res, err := db.ExecContext(ctx, insertQuery, params.UserID, params.CredentialID, params.PublicKey, params.AttestationType,
+			"", params.SignCount, string(transportsJSON), params.BackupEligible, params.BackupState, params.Name, now, now)
+		if err != nil {
+			return err
+		}
+		credentialID, err = res.LastInsertId()
+		return err
+	})
+	if err != nil {
+		return 0, err
+	}
+	return credentialID, nil
+}
+
+func (p *DatabasePasskeyProvider) getCredentialDirect(ctx context.Context, credentialIDB64 string) (userID int, signCount uint32, err error) {
+	err = p.runDBOpWithReconnect(func(db *sql.DB) error {
+		query := rewritePlaceholders(db, fmt.Sprintf(`SELECT user_id, sign_count FROM %s WHERE credential_id = ?`, p.tableNames.UserPasskeyCredentials))
+		return db.QueryRowContext(ctx, query, credentialIDB64).Scan(&userID, &signCount)
+	})
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return 0, 0, fmt.Errorf("Credential not found")
+		}
+		return 0, 0, fmt.Errorf("failed to get credential: %w", err)
+	}
+	return userID, signCount, nil
+}
+
+func (p *DatabasePasskeyProvider) updateCounterDirect(ctx context.Context, credentialIDB64 string, newCounter uint32) (cloneWarning bool, err error) {
+	err = p.runDBOpWithReconnect(func(db *sql.DB) error {
+		var oldCounter int
+		query := rewritePlaceholders(db, fmt.Sprintf(`SELECT sign_count FROM %s WHERE credential_id = ?`, p.tableNames.UserPasskeyCredentials))
+		if err := db.QueryRowContext(ctx, query, credentialIDB64).Scan(&oldCounter); err != nil {
+			if errors.Is(err, sql.ErrNoRows) {
+				return fmt.Errorf("Credential not found")
+			}
+			return err
+		}
+
+		if int(newCounter) <= oldCounter {
+			cloneWarning = true
+			updQuery := rewritePlaceholders(db, fmt.Sprintf(`UPDATE %s SET clone_warning = ? WHERE credential_id = ?`, p.tableNames.UserPasskeyCredentials))
+			_, err := db.ExecContext(ctx, updQuery, true, credentialIDB64)
+			return err
+		}
+
+		updQuery := rewritePlaceholders(db, fmt.Sprintf(`UPDATE %s SET sign_count = ?, last_used_at = ? WHERE credential_id = ?`, p.tableNames.UserPasskeyCredentials))
+		_, err := db.ExecContext(ctx, updQuery, newCounter, time.Now(), credentialIDB64)
+		return err
+	})
+	return cloneWarning, err
+}
+
+func (p *DatabasePasskeyProvider) getUserCredentialsDirect(ctx context.Context, userID int) ([]PasskeyCredential, error) {
+	var credentials []PasskeyCredential
+	err := p.runDBOpWithReconnect(func(db *sql.DB) error {
+		query := rewritePlaceholders(db, fmt.Sprintf(
+			`SELECT id, user_id, credential_id, public_key, attestation_type, aaguid, sign_count, clone_warning, transports, backup_eligible, backup_state, name, created_at, last_used_at
+			 FROM %s WHERE user_id = ? ORDER BY created_at DESC`, p.tableNames.UserPasskeyCredentials))
+		rows, err := db.QueryContext(ctx, query, userID)
+		if err != nil {
+			return err
+		}
+		defer rows.Close()
+
+		credentials = make([]PasskeyCredential, 0)
+		for rows.Next() {
+			var id, uid int
+			var credIDB64, pubKeyB64, attestationType, aaguidB64, name string
+			var signCount uint32
+			var cloneWarning, backupEligible, backupState bool
+			var transportsJSON sql.NullString
+			var createdAt, lastUsedAt time.Time
+
+			if err := rows.Scan(&id, &uid, &credIDB64, &pubKeyB64, &attestationType, &aaguidB64, &signCount,
+				&cloneWarning, &transportsJSON, &backupEligible, &backupState, &name, &createdAt, &lastUsedAt); err != nil {
+				return err
+			}
+
+			credID, err := base64.StdEncoding.DecodeString(credIDB64)
+			if err != nil {
+				continue
+			}
+			pubKey, err := base64.StdEncoding.DecodeString(pubKeyB64)
+			if err != nil {
+				continue
+			}
+			aaguid, _ := base64.StdEncoding.DecodeString(aaguidB64)
+
+			var transports []string
+			if transportsJSON.Valid && transportsJSON.String != "" {
+				_ = json.Unmarshal([]byte(transportsJSON.String), &transports)
+			}
+
+			credentials = append(credentials, PasskeyCredential{
+				ID:              fmt.Sprintf("%d", id),
+				UserID:          uid,
+				CredentialID:    credID,
+				PublicKey:       pubKey,
+				AttestationType: attestationType,
+				AAGUID:          aaguid,
+				SignCount:       signCount,
+				CloneWarning:    cloneWarning,
+				Transports:      transports,
+				BackupEligible:  backupEligible,
+				BackupState:     backupState,
+				Name:            name,
+				CreatedAt:       createdAt,
+				LastUsedAt:      lastUsedAt,
+			})
+		}
+		return rows.Err()
+	})
+	if err != nil {
+		return nil, fmt.Errorf("failed to get credentials: %w", err)
+	}
+	return credentials, nil
+}
+
+func (p *DatabasePasskeyProvider) deleteCredentialDirect(ctx context.Context, userID int, credentialIDB64 string) error {
+	return p.runDBOpWithReconnect(func(db *sql.DB) error {
+		query := rewritePlaceholders(db, fmt.Sprintf(`DELETE FROM %s WHERE user_id = ? AND credential_id = ?`, p.tableNames.UserPasskeyCredentials))
+		res, err := db.ExecContext(ctx, query, userID, credentialIDB64)
+		if err != nil {
+			return err
+		}
+		rows, err := res.RowsAffected()
+		if err != nil {
+			return err
+		}
+		if rows == 0 {
+			return fmt.Errorf("Credential not found")
+		}
+		return nil
+	})
+}
+
+func (p *DatabasePasskeyProvider) updateNameDirect(ctx context.Context, userID int, credentialIDB64, name string) error {
+	return p.runDBOpWithReconnect(func(db *sql.DB) error {
+		query := rewritePlaceholders(db, fmt.Sprintf(`UPDATE %s SET name = ? WHERE user_id = ? AND credential_id = ?`, p.tableNames.UserPasskeyCredentials))
+		res, err := db.ExecContext(ctx, query, name, userID, credentialIDB64)
+		if err != nil {
+			return err
+		}
+		rows, err := res.RowsAffected()
+		if err != nil {
+			return err
+		}
+		if rows == 0 {
+			return fmt.Errorf("Credential not found")
+		}
+		return nil
+	})
+}
+
+func (p *DatabasePasskeyProvider) getCredsByUsernameDirect(ctx context.Context, username string) (int, []struct {
+	ID         string   `json:"credential_id"`
+	Transports []string `json:"transports"`
+}, error) {
+	type credT = struct {
+		ID         string   `json:"credential_id"`
+		Transports []string `json:"transports"`
+	}
+	var userID int
+	var creds []credT
+
+	err := p.runDBOpWithReconnect(func(db *sql.DB) error {
+		userQuery := rewritePlaceholders(db, fmt.Sprintf(`SELECT id FROM %s WHERE username = ? AND is_active = ?`, p.tableNames.Users))
+		if err := db.QueryRowContext(ctx, userQuery, username, true).Scan(&userID); err != nil {
+			return err
+		}
+
+		query := rewritePlaceholders(db, fmt.Sprintf(`SELECT credential_id, transports FROM %s WHERE user_id = ?`, p.tableNames.UserPasskeyCredentials))
+		rows, err := db.QueryContext(ctx, query, userID)
+		if err != nil {
+			return err
+		}
+		defer rows.Close()
+
+		creds = make([]credT, 0)
+		for rows.Next() {
+			var credID string
+			var transportsJSON sql.NullString
+			if err := rows.Scan(&credID, &transportsJSON); err != nil {
+				return err
+			}
+			var transports []string
+			if transportsJSON.Valid && transportsJSON.String != "" {
+				_ = json.Unmarshal([]byte(transportsJSON.String), &transports)
+			}
+			creds = append(creds, credT{ID: credID, Transports: transports})
+		}
+		return rows.Err()
+	})
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return 0, nil, fmt.Errorf("User not found")
+		}
+		return 0, nil, fmt.Errorf("failed to get credentials: %w", err)
+	}
+	return userID, creds, nil
+}
diff --git a/pkg/security/providers.go b/pkg/security/providers.go
index 385d16d..c91bf28 100644
--- a/pkg/security/providers.go
+++ b/pkg/security/providers.go
@@ -71,12 +71,15 @@ func (a *HeaderAuthenticator) Authenticate(r *http.Request) (*UserContext, error
 // Also supports multiple OAuth2 providers configured with WithOAuth2()
 // Also supports passkey authentication configured with WithPasskey()
 type DatabaseAuthenticator struct {
-	db        *sql.DB
-	dbMu      sync.RWMutex
-	dbFactory func() (*sql.DB, error)
-	cache     *cache.Cache
-	cacheTTL  time.Duration
-	sqlNames  *SQLNames
+	db         *sql.DB
+	dbMu       sync.RWMutex
+	dbFactory  func() (*sql.DB, error)
+	cache      *cache.Cache
+	cacheTTL   time.Duration
+	sqlNames   *SQLNames
+	tableNames *TableNames
+	queryMode  QueryMode
+	capability *dbCapability
 
 	// Cookie session support (optional, gated by enableCookieSession)
 	enableCookieSession bool
@@ -105,6 +108,10 @@ type DatabaseAuthenticatorOptions struct {
 	// SQLNames provides custom SQL procedure/function names. If nil, uses DefaultSQLNames().
 	// Partial overrides are supported: only set the fields you want to change.
 	SQLNames *SQLNames
+	// TableNames provides custom table names for Direct mode. If nil, uses DefaultTableNames().
+	TableNames *TableNames
+	// QueryMode selects stored-procedure vs Direct-mode SQL. Default (zero value) is ModeAuto.
+	QueryMode QueryMode
 	// DBFactory is called to obtain a fresh *sql.DB when the existing connection is closed.
 	// If nil, reconnection is disabled.
 	DBFactory func() (*sql.DB, error)
@@ -139,6 +146,7 @@ func NewDatabaseAuthenticatorWithOptions(db *sql.DB, opts DatabaseAuthenticatorO
 	}
 
 	sqlNames := MergeSQLNames(DefaultSQLNames(), opts.SQLNames)
+	tableNames := resolveTableNames(opts.TableNames)
 
 	return &DatabaseAuthenticator{
 		db:                   db,
@@ -146,6 +154,9 @@ func NewDatabaseAuthenticatorWithOptions(db *sql.DB, opts DatabaseAuthenticatorO
 		cache:                cacheInstance,
 		cacheTTL:             opts.CacheTTL,
 		sqlNames:             sqlNames,
+		tableNames:           tableNames,
+		queryMode:            opts.QueryMode,
+		capability:           newDBCapability(),
 		passkeyProvider:      opts.PasskeyProvider,
 		enableCookieSession:  opts.EnableCookieSession,
 		cookieOptions:        opts.CookieOptions,
@@ -170,6 +181,9 @@ func (a *DatabaseAuthenticator) reconnectDB() error {
 	a.dbMu.Lock()
 	a.db = newDB
 	a.dbMu.Unlock()
+	if a.capability != nil {
+		a.capability.reset()
+	}
 	return nil
 }
 
@@ -194,6 +208,9 @@ func (a *DatabaseAuthenticator) SetAuthenticateCallback(fn func(r *http.Request)
 }
 
 func (a *DatabaseAuthenticator) Login(ctx context.Context, req LoginRequest) (*LoginResponse, error) {
+	if !a.capability.ShouldUseProcedure(ctx, a.queryMode, a.getDB(), a.sqlNames.Login) {
+		return a.loginDirect(ctx, req)
+	}
 	// Convert LoginRequest to JSON
 	reqJSON, err := json.Marshal(req)
 	if err != nil {
@@ -230,6 +247,9 @@ func (a *DatabaseAuthenticator) Login(ctx context.Context, req LoginRequest) (*L
 
 // Register implements Registrable interface
 func (a *DatabaseAuthenticator) Register(ctx context.Context, req RegisterRequest) (*LoginResponse, error) {
+	if !a.capability.ShouldUseProcedure(ctx, a.queryMode, a.getDB(), a.sqlNames.Register) {
+		return a.registerDirect(ctx, req)
+	}
 	// Convert RegisterRequest to JSON
 	reqJSON, err := json.Marshal(req)
 	if err != nil {
@@ -265,6 +285,9 @@ func (a *DatabaseAuthenticator) Register(ctx context.Context, req RegisterReques
 }
 
 func (a *DatabaseAuthenticator) Logout(ctx context.Context, req LogoutRequest) error {
+	if !a.capability.ShouldUseProcedure(ctx, a.queryMode, a.getDB(), a.sqlNames.Logout) {
+		return a.logoutDirect(ctx, req)
+	}
 	// Convert LogoutRequest to JSON
 	reqJSON, err := json.Marshal(req)
 	if err != nil {
@@ -378,6 +401,10 @@ func (a *DatabaseAuthenticator) Authenticate(r *http.Request) (*UserContext, err
 		var userCtx UserContext
 		err := a.cache.GetOrSet(r.Context(), cacheKey, &userCtx, a.cacheTTL, func() (any, error) {
 			// This function is called only if cache miss
+			if !a.capability.ShouldUseProcedure(r.Context(), a.queryMode, a.getDB(), a.sqlNames.Session) {
+				return a.sessionDirect(r.Context(), token)
+			}
+
 			var success bool
 			var errorMsg sql.NullString
 			var userJSON sql.NullString
@@ -453,6 +480,11 @@ func (a *DatabaseAuthenticator) ClearUserCache(userID int) error {
 
 // updateSessionActivity updates the last activity timestamp for the session
 func (a *DatabaseAuthenticator) updateSessionActivity(ctx context.Context, sessionToken string, userCtx *UserContext) {
+	if !a.capability.ShouldUseProcedure(ctx, a.queryMode, a.getDB(), a.sqlNames.SessionUpdate) {
+		_ = a.updateSessionActivityDirect(ctx, sessionToken)
+		return
+	}
+
 	// Convert UserContext to JSON
 	userJSON, err := json.Marshal(userCtx)
 	if err != nil {
@@ -471,6 +503,9 @@ func (a *DatabaseAuthenticator) updateSessionActivity(ctx context.Context, sessi
 
 // RefreshToken implements Refreshable interface
 func (a *DatabaseAuthenticator) RefreshToken(ctx context.Context, refreshToken string) (*LoginResponse, error) {
+	if !a.capability.ShouldUseProcedure(ctx, a.queryMode, a.getDB(), a.sqlNames.RefreshToken) {
+		return a.refreshTokenDirect(ctx, refreshToken)
+	}
 	// First, we need to get the current user context for the refresh token
 	var success bool
 	var errorMsg sql.NullString
@@ -528,18 +563,23 @@ func (a *DatabaseAuthenticator) RefreshToken(ctx context.Context, refreshToken s
 // Procedure names are configurable via SQLNames (see DefaultSQLNames for defaults)
 // NOTE: JWT signing/verification requires github.com/golang-jwt/jwt/v5 to be installed and imported
 type JWTAuthenticator struct {
-	secretKey []byte
-	db        *sql.DB
-	dbMu      sync.RWMutex
-	dbFactory func() (*sql.DB, error)
-	sqlNames  *SQLNames
+	secretKey  []byte
+	db         *sql.DB
+	dbMu       sync.RWMutex
+	dbFactory  func() (*sql.DB, error)
+	sqlNames   *SQLNames
+	tableNames *TableNames
+	queryMode  QueryMode
+	capability *dbCapability
 }
 
 func NewJWTAuthenticator(secretKey string, db *sql.DB, names ...*SQLNames) *JWTAuthenticator {
 	return &JWTAuthenticator{
-		secretKey: []byte(secretKey),
-		db:        db,
-		sqlNames:  resolveSQLNames(names...),
+		secretKey:  []byte(secretKey),
+		db:         db,
+		sqlNames:   resolveSQLNames(names...),
+		tableNames: DefaultTableNames(),
+		capability: newDBCapability(),
 	}
 }
 
@@ -549,6 +589,18 @@ func (a *JWTAuthenticator) WithDBFactory(factory func() (*sql.DB, error)) *JWTAu
 	return a
 }
 
+// WithTableNames configures Direct-mode table names. If names is nil, defaults are used.
+func (a *JWTAuthenticator) WithTableNames(names *TableNames) *JWTAuthenticator {
+	a.tableNames = resolveTableNames(names)
+	return a
+}
+
+// WithQueryMode selects stored-procedure vs Direct-mode SQL (default ModeAuto).
+func (a *JWTAuthenticator) WithQueryMode(mode QueryMode) *JWTAuthenticator {
+	a.queryMode = mode
+	return a
+}
+
 func (a *JWTAuthenticator) getDB() *sql.DB {
 	a.dbMu.RLock()
 	defer a.dbMu.RUnlock()
@@ -566,10 +618,17 @@ func (a *JWTAuthenticator) reconnectDB() error {
 	a.dbMu.Lock()
 	a.db = newDB
 	a.dbMu.Unlock()
+	if a.capability != nil {
+		a.capability.reset()
+	}
 	return nil
 }
 
 func (a *JWTAuthenticator) Login(ctx context.Context, req LoginRequest) (*LoginResponse, error) {
+	if !a.capability.ShouldUseProcedure(ctx, a.queryMode, a.getDB(), a.sqlNames.JWTLogin) {
+		return a.jwtLoginDirect(ctx, req)
+	}
+
 	var success bool
 	var errorMsg sql.NullString
 	var userJSON []byte
@@ -632,6 +691,10 @@ func (a *JWTAuthenticator) Login(ctx context.Context, req LoginRequest) (*LoginR
 }
 
 func (a *JWTAuthenticator) Logout(ctx context.Context, req LogoutRequest) error {
+	if !a.capability.ShouldUseProcedure(ctx, a.queryMode, a.getDB(), a.sqlNames.JWTLogout) {
+		return a.jwtLogoutDirect(ctx, req)
+	}
+
 	var success bool
 	var errorMsg sql.NullString
 
@@ -681,14 +744,23 @@ func (a *JWTAuthenticator) Authenticate(r *http.Request) (*UserContext, error) {
 // All database operations go through stored procedures
 // Procedure names are configurable via SQLNames (see DefaultSQLNames for defaults)
 type DatabaseColumnSecurityProvider struct {
-	db        *sql.DB
-	dbMu      sync.RWMutex
-	dbFactory func() (*sql.DB, error)
-	sqlNames  *SQLNames
+	db         *sql.DB
+	dbMu       sync.RWMutex
+	dbFactory  func() (*sql.DB, error)
+	sqlNames   *SQLNames
+	queryMode  QueryMode
+	capability *dbCapability
 }
 
 func NewDatabaseColumnSecurityProvider(db *sql.DB, names ...*SQLNames) *DatabaseColumnSecurityProvider {
-	return &DatabaseColumnSecurityProvider{db: db, sqlNames: resolveSQLNames(names...)}
+	return &DatabaseColumnSecurityProvider{db: db, sqlNames: resolveSQLNames(names...), capability: newDBCapability()}
+}
+
+// WithQueryMode selects stored-procedure vs Direct-mode SQL (default ModeAuto).
+// Direct mode is unsupported for column security (see ErrDirectModeUnsupported).
+func (p *DatabaseColumnSecurityProvider) WithQueryMode(mode QueryMode) *DatabaseColumnSecurityProvider {
+	p.queryMode = mode
+	return p
 }
 
 func (p *DatabaseColumnSecurityProvider) WithDBFactory(factory func() (*sql.DB, error)) *DatabaseColumnSecurityProvider {
@@ -713,10 +785,17 @@ func (p *DatabaseColumnSecurityProvider) reconnectDB() error {
 	p.dbMu.Lock()
 	p.db = newDB
 	p.dbMu.Unlock()
+	if p.capability != nil {
+		p.capability.reset()
+	}
 	return nil
 }
 
 func (p *DatabaseColumnSecurityProvider) GetColumnSecurity(ctx context.Context, userID int, schema, table string) ([]ColumnSecurity, error) {
+	if !p.capability.ShouldUseProcedure(ctx, p.queryMode, p.getDB(), p.sqlNames.ColumnSecurity) {
+		return nil, ErrDirectModeUnsupported
+	}
+
 	var rules []ColumnSecurity
 
 	var success bool
@@ -781,14 +860,23 @@ func (p *DatabaseColumnSecurityProvider) GetColumnSecurity(ctx context.Context,
 // All database operations go through stored procedures
 // Procedure names are configurable via SQLNames (see DefaultSQLNames for defaults)
 type DatabaseRowSecurityProvider struct {
-	db        *sql.DB
-	dbMu      sync.RWMutex
-	dbFactory func() (*sql.DB, error)
-	sqlNames  *SQLNames
+	db         *sql.DB
+	dbMu       sync.RWMutex
+	dbFactory  func() (*sql.DB, error)
+	sqlNames   *SQLNames
+	queryMode  QueryMode
+	capability *dbCapability
 }
 
 func NewDatabaseRowSecurityProvider(db *sql.DB, names ...*SQLNames) *DatabaseRowSecurityProvider {
-	return &DatabaseRowSecurityProvider{db: db, sqlNames: resolveSQLNames(names...)}
+	return &DatabaseRowSecurityProvider{db: db, sqlNames: resolveSQLNames(names...), capability: newDBCapability()}
+}
+
+// WithQueryMode selects stored-procedure vs Direct-mode SQL (default ModeAuto).
+// Direct mode is unsupported for row security (see ErrDirectModeUnsupported).
+func (p *DatabaseRowSecurityProvider) WithQueryMode(mode QueryMode) *DatabaseRowSecurityProvider {
+	p.queryMode = mode
+	return p
 }
 
 func (p *DatabaseRowSecurityProvider) WithDBFactory(factory func() (*sql.DB, error)) *DatabaseRowSecurityProvider {
@@ -813,10 +901,17 @@ func (p *DatabaseRowSecurityProvider) reconnectDB() error {
 	p.dbMu.Lock()
 	p.db = newDB
 	p.dbMu.Unlock()
+	if p.capability != nil {
+		p.capability.reset()
+	}
 	return nil
 }
 
 func (p *DatabaseRowSecurityProvider) GetRowSecurity(ctx context.Context, userID int, schema, table string) (RowSecurity, error) {
+	if !p.capability.ShouldUseProcedure(ctx, p.queryMode, p.getDB(), p.sqlNames.RowSecurity) {
+		return RowSecurity{}, ErrDirectModeUnsupported
+	}
+
 	var template string
 	var hasBlock bool
 
@@ -950,6 +1045,9 @@ func generateRandomString(length int) string {
 // RequestPasswordReset implements PasswordResettable. It calls the stored procedure
 // resolvespec_password_reset_request and returns the reset token and expiry.
 func (a *DatabaseAuthenticator) RequestPasswordReset(ctx context.Context, req PasswordResetRequest) (*PasswordResetResponse, error) {
+	if !a.capability.ShouldUseProcedure(ctx, a.queryMode, a.getDB(), a.sqlNames.PasswordResetRequest) {
+		return a.requestPasswordResetDirect(ctx, req)
+	}
 	reqJSON, err := json.Marshal(req)
 	if err != nil {
 		return nil, fmt.Errorf("failed to marshal password reset request: %w", err)
@@ -987,6 +1085,9 @@ func (a *DatabaseAuthenticator) RequestPasswordReset(ctx context.Context, req Pa
 // CompletePasswordReset implements PasswordResettable. It validates the token and
 // updates the user's password via resolvespec_password_reset.
 func (a *DatabaseAuthenticator) CompletePasswordReset(ctx context.Context, req PasswordResetCompleteRequest) error {
+	if !a.capability.ShouldUseProcedure(ctx, a.queryMode, a.getDB(), a.sqlNames.PasswordResetComplete) {
+		return a.completePasswordResetDirect(ctx, req)
+	}
 	reqJSON, err := json.Marshal(req)
 	if err != nil {
 		return fmt.Errorf("failed to marshal password reset complete request: %w", err)
diff --git a/pkg/security/providers_direct.go b/pkg/security/providers_direct.go
new file mode 100644
index 0000000..c884fb7
--- /dev/null
+++ b/pkg/security/providers_direct.go
@@ -0,0 +1,473 @@
+package security
+
+import (
+	"context"
+	"crypto/rand"
+	"crypto/sha256"
+	"database/sql"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"strings"
+	"time"
+)
+
+// Direct-mode implementations for DatabaseAuthenticator and JWTAuthenticator.
+// These mirror the plpgsql bodies in database_schema.sql using plain
+// parameterized SQL against the configured TableNames, so they work on
+// SQLite, MySQL, or Postgres without the resolvespec_* functions installed.
+//
+// Password verification is intentionally not implemented here: the stored
+// procedures never verify the password hash either (see the TODOs in
+// database_schema.sql), so Direct mode matches that behavior exactly rather
+// than introducing a mismatch between modes.
+
+var (
+	errUsernameExists = errors.New("Username already exists")
+	errEmailExists    = errors.New("Email already exists")
+)
+
+func (a *DatabaseAuthenticator) loginDirect(ctx context.Context, req LoginRequest) (*LoginResponse, error) {
+	var userID int
+	var email, roles, programUserTable sql.NullString
+	var userLevel, programUserID sql.NullInt64
+
+	err := a.runDBOpWithReconnect(func(db *sql.DB) error {
+		query := rewritePlaceholders(db, fmt.Sprintf(
+			`SELECT id, email, user_level, roles, program_user_id, program_user_table FROM %s WHERE username = ? AND is_active = ?`,
+			a.tableNames.Users))
+		return db.QueryRowContext(ctx, query, req.Username, true).Scan(&userID, &email, &userLevel, &roles, &programUserID, &programUserTable)
+	})
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return nil, fmt.Errorf("Invalid credentials")
+		}
+		return nil, fmt.Errorf("login query failed: %w", err)
+	}
+
+	sessionToken, err := generateSessionToken()
+	if err != nil {
+		return nil, fmt.Errorf("failed to generate session token: %w", err)
+	}
+	now := time.Now()
+	expiresAt := now.Add(24 * time.Hour)
+	ipAddress, userAgent := claimStrings(req.Claims)
+
+	err = a.runDBOpWithReconnect(func(db *sql.DB) error {
+		insertQuery := rewritePlaceholders(db, fmt.Sprintf(
+			`INSERT INTO %s (session_token, user_id, expires_at, ip_address, user_agent, last_activity_at, created_at) VALUES (?, ?, ?, ?, ?, ?, ?)`,
+			a.tableNames.UserSessions))
+		if _, err := db.ExecContext(ctx, insertQuery, sessionToken, userID, expiresAt, ipAddress, userAgent, now, now); err != nil {
+			return err
+		}
+		updateQuery := rewritePlaceholders(db, fmt.Sprintf(`UPDATE %s SET last_login_at = ? WHERE id = ?`, a.tableNames.Users))
+		_, err := db.ExecContext(ctx, updateQuery, now, userID)
+		return err
+	})
+	if err != nil {
+		return nil, fmt.Errorf("login query failed: %w", err)
+	}
+
+	userCtx := &UserContext{
+		UserID:           userID,
+		UserName:         req.Username,
+		Email:            email.String,
+		UserLevel:        int(userLevel.Int64),
+		Roles:            parseRoles(roles.String),
+		SessionID:        sessionToken,
+		ProgramUserID:    int(programUserID.Int64),
+		ProgramUserTable: programUserTable.String,
+	}
+
+	return &LoginResponse{
+		Token:     sessionToken,
+		User:      userCtx,
+		ExpiresIn: 86400,
+	}, nil
+}
+
+func (a *DatabaseAuthenticator) registerDirect(ctx context.Context, req RegisterRequest) (*LoginResponse, error) {
+	if req.Username == "" {
+		return nil, fmt.Errorf("Username is required")
+	}
+	if req.Email == "" {
+		return nil, fmt.Errorf("Email is required")
+	}
+	if req.Password == "" {
+		return nil, fmt.Errorf("Password is required")
+	}
+
+	rolesStr := strings.Join(req.Roles, ",")
+	now := time.Now()
+	ipAddress, userAgent := claimStrings(req.Claims)
+
+	var userID int64
+	err := a.runDBOpWithReconnect(func(db *sql.DB) error {
+		var count int
+		checkQuery := rewritePlaceholders(db, fmt.Sprintf(`SELECT COUNT(*) FROM %s WHERE username = ?`, a.tableNames.Users))
+		if err := db.QueryRowContext(ctx, checkQuery, req.Username).Scan(&count); err != nil {
+			return err
+		}
+		if count > 0 {
+			return errUsernameExists
+		}
+		checkQuery2 := rewritePlaceholders(db, fmt.Sprintf(`SELECT COUNT(*) FROM %s WHERE email = ?`, a.tableNames.Users))
+		if err := db.QueryRowContext(ctx, checkQuery2, req.Email).Scan(&count); err != nil {
+			return err
+		}
+		if count > 0 {
+			return errEmailExists
+		}
+
+		insertQuery := rewritePlaceholders(db, fmt.Sprintf(
+			`INSERT INTO %s (username, email, password, user_level, roles, is_active, created_at, updated_at, program_user_id, program_user_table) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
+			a.tableNames.Users))
+		res, err := db.ExecContext(ctx, insertQuery, req.Username, req.Email, req.Password, req.UserLevel, rolesStr, true, now, now, 0, "")
+		if err != nil {
+			return err
+		}
+		userID, err = res.LastInsertId()
+		return err
+	})
+	if err != nil {
+		if errors.Is(err, errUsernameExists) {
+			return nil, errUsernameExists
+		}
+		if errors.Is(err, errEmailExists) {
+			return nil, errEmailExists
+		}
+		return nil, fmt.Errorf("register query failed: %w", err)
+	}
+
+	sessionToken, err := generateSessionToken()
+	if err != nil {
+		return nil, fmt.Errorf("failed to generate session token: %w", err)
+	}
+	expiresAt := now.Add(24 * time.Hour)
+
+	err = a.runDBOpWithReconnect(func(db *sql.DB) error {
+		insertSession := rewritePlaceholders(db, fmt.Sprintf(
+			`INSERT INTO %s (session_token, user_id, expires_at, ip_address, user_agent, last_activity_at, created_at) VALUES (?, ?, ?, ?, ?, ?, ?)`,
+			a.tableNames.UserSessions))
+		if _, err := db.ExecContext(ctx, insertSession, sessionToken, userID, expiresAt, ipAddress, userAgent, now, now); err != nil {
+			return err
+		}
+		updUser := rewritePlaceholders(db, fmt.Sprintf(`UPDATE %s SET last_login_at = ? WHERE id = ?`, a.tableNames.Users))
+		_, err := db.ExecContext(ctx, updUser, now, userID)
+		return err
+	})
+	if err != nil {
+		return nil, fmt.Errorf("register query failed: %w", err)
+	}
+
+	userCtx := &UserContext{
+		UserID:           int(userID),
+		UserName:         req.Username,
+		Email:            req.Email,
+		UserLevel:        req.UserLevel,
+		Roles:            parseRoles(rolesStr),
+		SessionID:        sessionToken,
+		ProgramUserID:    0,
+		ProgramUserTable: "",
+	}
+
+	return &LoginResponse{
+		Token:     sessionToken,
+		User:      userCtx,
+		ExpiresIn: 86400,
+	}, nil
+}
+
+func (a *DatabaseAuthenticator) logoutDirect(ctx context.Context, req LogoutRequest) error {
+	token := req.Token
+	token = strings.TrimPrefix(token, "Bearer ")
+	token = strings.TrimPrefix(token, "bearer ")
+
+	var rows int64
+	err := a.runDBOpWithReconnect(func(db *sql.DB) error {
+		query := rewritePlaceholders(db, fmt.Sprintf(`DELETE FROM %s WHERE session_token = ? AND user_id = ?`, a.tableNames.UserSessions))
+		res, err := db.ExecContext(ctx, query, token, req.UserID)
+		if err != nil {
+			return err
+		}
+		rows, err = res.RowsAffected()
+		return err
+	})
+	if err != nil {
+		return fmt.Errorf("logout query failed: %w", err)
+	}
+	if rows == 0 {
+		return fmt.Errorf("Session not found")
+	}
+
+	if req.Token != "" {
+		cacheKey := fmt.Sprintf("auth:session:%s", req.Token)
+		_ = a.cache.Delete(ctx, cacheKey)
+	}
+	return nil
+}
+
+func (a *DatabaseAuthenticator) sessionDirect(ctx context.Context, token string) (*UserContext, error) {
+	var userID int
+	var username, email, roles, programUserTable sql.NullString
+	var userLevel, programUserID sql.NullInt64
+
+	err := a.runDBOpWithReconnect(func(db *sql.DB) error {
+		query := rewritePlaceholders(db, fmt.Sprintf(
+			`SELECT s.user_id, u.username, u.email, u.user_level, u.roles, u.program_user_id, u.program_user_table
+			 FROM %s s JOIN %s u ON s.user_id = u.id
+			 WHERE s.session_token = ? AND s.expires_at > ? AND u.is_active = ?`,
+			a.tableNames.UserSessions, a.tableNames.Users))
+		return db.QueryRowContext(ctx, query, token, time.Now(), true).Scan(&userID, &username, &email, &userLevel, &roles, &programUserID, &programUserTable)
+	})
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return nil, fmt.Errorf("Invalid or expired session")
+		}
+		return nil, fmt.Errorf("session query failed: %w", err)
+	}
+
+	return &UserContext{
+		UserID:           userID,
+		UserName:         username.String,
+		Email:            email.String,
+		UserLevel:        int(userLevel.Int64),
+		SessionID:        token,
+		Roles:            parseRoles(roles.String),
+		ProgramUserID:    int(programUserID.Int64),
+		ProgramUserTable: programUserTable.String,
+	}, nil
+}
+
+func (a *DatabaseAuthenticator) updateSessionActivityDirect(ctx context.Context, sessionToken string) error {
+	return a.runDBOpWithReconnect(func(db *sql.DB) error {
+		query := rewritePlaceholders(db, fmt.Sprintf(`UPDATE %s SET last_activity_at = ? WHERE session_token = ? AND expires_at > ?`, a.tableNames.UserSessions))
+		_, err := db.ExecContext(ctx, query, time.Now(), sessionToken, time.Now())
+		return err
+	})
+}
+
+func (a *DatabaseAuthenticator) refreshTokenDirect(ctx context.Context, oldToken string) (*LoginResponse, error) {
+	var userID int
+	var username, email, roles, ipAddress, userAgent, programUserTable sql.NullString
+	var userLevel, programUserID sql.NullInt64
+
+	err := a.runDBOpWithReconnect(func(db *sql.DB) error {
+		query := rewritePlaceholders(db, fmt.Sprintf(
+			`SELECT s.user_id, u.username, u.email, u.user_level, u.roles, s.ip_address, s.user_agent, u.program_user_id, u.program_user_table
+			 FROM %s s JOIN %s u ON s.user_id = u.id
+			 WHERE s.session_token = ? AND s.expires_at > ? AND u.is_active = ?`,
+			a.tableNames.UserSessions, a.tableNames.Users))
+		return db.QueryRowContext(ctx, query, oldToken, time.Now(), true).Scan(&userID, &username, &email, &userLevel, &roles, &ipAddress, &userAgent, &programUserID, &programUserTable)
+	})
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return nil, fmt.Errorf("Invalid or expired refresh token")
+		}
+		return nil, fmt.Errorf("refresh token query failed: %w", err)
+	}
+
+	newToken, err := generateSessionToken()
+	if err != nil {
+		return nil, fmt.Errorf("failed to generate session token: %w", err)
+	}
+	now := time.Now()
+	expiresAt := now.Add(24 * time.Hour)
+
+	err = a.runDBOpWithReconnect(func(db *sql.DB) error {
+		insertQuery := rewritePlaceholders(db, fmt.Sprintf(
+			`INSERT INTO %s (session_token, user_id, expires_at, ip_address, user_agent, last_activity_at, created_at) VALUES (?, ?, ?, ?, ?, ?, ?)`,
+			a.tableNames.UserSessions))
+		if _, err := db.ExecContext(ctx, insertQuery, newToken, userID, expiresAt, ipAddress.String, userAgent.String, now, now); err != nil {
+			return err
+		}
+		delQuery := rewritePlaceholders(db, fmt.Sprintf(`DELETE FROM %s WHERE session_token = ?`, a.tableNames.UserSessions))
+		_, err := db.ExecContext(ctx, delQuery, oldToken)
+		return err
+	})
+	if err != nil {
+		return nil, fmt.Errorf("refresh token generation failed: %w", err)
+	}
+
+	userCtx := &UserContext{
+		UserID:           userID,
+		UserName:         username.String,
+		Email:            email.String,
+		UserLevel:        int(userLevel.Int64),
+		SessionID:        newToken,
+		Roles:            parseRoles(roles.String),
+		ProgramUserID:    int(programUserID.Int64),
+		ProgramUserTable: programUserTable.String,
+	}
+
+	return &LoginResponse{
+		Token:     newToken,
+		User:      userCtx,
+		ExpiresIn: int64(24 * time.Hour.Seconds()),
+	}, nil
+}
+
+func (a *DatabaseAuthenticator) requestPasswordResetDirect(ctx context.Context, req PasswordResetRequest) (*PasswordResetResponse, error) {
+	if req.Email == "" && req.Username == "" {
+		return nil, fmt.Errorf("email or username is required")
+	}
+
+	var userID int
+	err := a.runDBOpWithReconnect(func(db *sql.DB) error {
+		var query string
+		var arg string
+		if req.Email != "" {
+			query = rewritePlaceholders(db, fmt.Sprintf(`SELECT id FROM %s WHERE email = ? AND is_active = ?`, a.tableNames.Users))
+			arg = req.Email
+		} else {
+			query = rewritePlaceholders(db, fmt.Sprintf(`SELECT id FROM %s WHERE username = ? AND is_active = ?`, a.tableNames.Users))
+			arg = req.Username
+		}
+		return db.QueryRowContext(ctx, query, arg, true).Scan(&userID)
+	})
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			// Return generic success even when user not found to avoid user enumeration.
+			return &PasswordResetResponse{Token: "", ExpiresIn: 0}, nil
+		}
+		return nil, fmt.Errorf("password reset request query failed: %w", err)
+	}
+
+	rawBytes := make([]byte, 32)
+	if _, err := rand.Read(rawBytes); err != nil {
+		return nil, fmt.Errorf("failed to generate reset token: %w", err)
+	}
+	rawToken := hex.EncodeToString(rawBytes)
+	hash := sha256.Sum256([]byte(rawToken))
+	tokenHash := hex.EncodeToString(hash[:])
+	now := time.Now()
+	expiresAt := now.Add(1 * time.Hour)
+
+	err = a.runDBOpWithReconnect(func(db *sql.DB) error {
+		delQuery := rewritePlaceholders(db, fmt.Sprintf(`DELETE FROM %s WHERE user_id = ? AND used = ?`, a.tableNames.UserPasswordResets))
+		if _, err := db.ExecContext(ctx, delQuery, userID, false); err != nil {
+			return err
+		}
+		insQuery := rewritePlaceholders(db, fmt.Sprintf(`INSERT INTO %s (user_id, token_hash, expires_at, created_at, used) VALUES (?, ?, ?, ?, ?)`, a.tableNames.UserPasswordResets))
+		_, err := db.ExecContext(ctx, insQuery, userID, tokenHash, expiresAt, now, false)
+		return err
+	})
+	if err != nil {
+		return nil, fmt.Errorf("password reset request query failed: %w", err)
+	}
+
+	return &PasswordResetResponse{Token: rawToken, ExpiresIn: 3600}, nil
+}
+
+func (a *DatabaseAuthenticator) completePasswordResetDirect(ctx context.Context, req PasswordResetCompleteRequest) error {
+	if req.Token == "" {
+		return fmt.Errorf("token is required")
+	}
+	if req.NewPassword == "" {
+		return fmt.Errorf("new_password is required")
+	}
+
+	hash := sha256.Sum256([]byte(req.Token))
+	tokenHash := hex.EncodeToString(hash[:])
+
+	var resetID, userID int
+	var expiresAt time.Time
+	err := a.runDBOpWithReconnect(func(db *sql.DB) error {
+		query := rewritePlaceholders(db, fmt.Sprintf(`SELECT id, user_id, expires_at FROM %s WHERE token_hash = ? AND used = ?`, a.tableNames.UserPasswordResets))
+		return db.QueryRowContext(ctx, query, tokenHash, false).Scan(&resetID, &userID, &expiresAt)
+	})
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return fmt.Errorf("invalid or expired token")
+		}
+		return fmt.Errorf("password reset complete query failed: %w", err)
+	}
+	if !expiresAt.After(time.Now()) {
+		return fmt.Errorf("invalid or expired token")
+	}
+
+	now := time.Now()
+	err = a.runDBOpWithReconnect(func(db *sql.DB) error {
+		updUser := rewritePlaceholders(db, fmt.Sprintf(`UPDATE %s SET password = ?, updated_at = ? WHERE id = ?`, a.tableNames.Users))
+		if _, err := db.ExecContext(ctx, updUser, req.NewPassword, now, userID); err != nil {
+			return err
+		}
+		delSessions := rewritePlaceholders(db, fmt.Sprintf(`DELETE FROM %s WHERE user_id = ?`, a.tableNames.UserSessions))
+		if _, err := db.ExecContext(ctx, delSessions, userID); err != nil {
+			return err
+		}
+		updReset := rewritePlaceholders(db, fmt.Sprintf(`UPDATE %s SET used = ?, used_at = ? WHERE id = ?`, a.tableNames.UserPasswordResets))
+		_, err := db.ExecContext(ctx, updReset, true, now, resetID)
+		return err
+	})
+	if err != nil {
+		return fmt.Errorf("password reset complete query failed: %w", err)
+	}
+	return nil
+}
+
+// claimStrings extracts ip_address/user_agent from a request's Claims map, mirroring
+// p_request->'claims'->>'ip_address' / 'user_agent' in the plpgsql procedures.
+func claimStrings(claims map[string]any) (ipAddress, userAgent string) {
+	if claims == nil {
+		return "", ""
+	}
+	if v, ok := claims["ip_address"].(string); ok {
+		ipAddress = v
+	}
+	if v, ok := claims["user_agent"].(string); ok {
+		userAgent = v
+	}
+	return ipAddress, userAgent
+}
+
+// jwtLoginDirect mirrors resolvespec_jwt_login.
+func (a *JWTAuthenticator) jwtLoginDirect(ctx context.Context, req LoginRequest) (*LoginResponse, error) {
+	var userID int
+	var email, roles sql.NullString
+	var userLevel sql.NullInt64
+
+	runQuery := func() error {
+		query := rewritePlaceholders(a.getDB(), fmt.Sprintf(`SELECT id, email, user_level, roles FROM %s WHERE username = ? AND is_active = ?`, a.tableNames.Users))
+		return a.getDB().QueryRowContext(ctx, query, req.Username, true).Scan(&userID, &email, &userLevel, &roles)
+	}
+	err := runQuery()
+	if isDBClosed(err) {
+		if reconnErr := a.reconnectDB(); reconnErr == nil {
+			err = runQuery()
+		}
+	}
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return nil, fmt.Errorf("invalid credentials")
+		}
+		return nil, fmt.Errorf("login query failed: %w", err)
+	}
+
+	expiresAt := time.Now().Add(24 * time.Hour)
+	tokenString := fmt.Sprintf("token_%d_%d", userID, expiresAt.Unix())
+
+	return &LoginResponse{
+		Token: tokenString,
+		User: &UserContext{
+			UserID:    userID,
+			UserName:  req.Username,
+			Email:     email.String,
+			UserLevel: int(userLevel.Int64),
+			Roles:     parseRoles(roles.String),
+		},
+		ExpiresIn: int64(24 * time.Hour.Seconds()),
+	}, nil
+}
+
+// jwtLogoutDirect mirrors resolvespec_jwt_logout (adds token to the blacklist table).
+func (a *JWTAuthenticator) jwtLogoutDirect(ctx context.Context, req LogoutRequest) error {
+	db := a.getDB()
+	expiresAt := time.Now().Add(24 * time.Hour)
+	query := rewritePlaceholders(db, fmt.Sprintf(`INSERT INTO %s (token, user_id, expires_at, created_at) VALUES (?, ?, ?, ?)`, a.tableNames.TokenBlacklist))
+	_, err := db.ExecContext(ctx, query, req.Token, req.UserID, expiresAt, time.Now())
+	if err != nil {
+		return fmt.Errorf("logout query failed: %w", err)
+	}
+	return nil
+}
diff --git a/pkg/security/query_mode.go b/pkg/security/query_mode.go
new file mode 100644
index 0000000..9c040d1
--- /dev/null
+++ b/pkg/security/query_mode.go
@@ -0,0 +1,169 @@
+package security
+
+import (
+	"context"
+	"crypto/rand"
+	"database/sql"
+	"encoding/hex"
+	"fmt"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+)
+
+// QueryMode selects how a provider talks to the database: via the configured
+// resolvespec_* stored procedure (ModeProcedure), via portable Go/SQL logic
+// (ModeDirect), or auto-detected per connection (ModeAuto, the default).
+type QueryMode int
+
+const (
+	// ModeAuto probes whether the configured stored procedure exists on a
+	// Postgres connection and uses it if so, otherwise falls back to Direct mode.
+	ModeAuto QueryMode = iota
+	// ModeProcedure always calls the configured resolvespec_* stored procedure.
+	ModeProcedure
+	// ModeDirect always uses the portable Go/SQL implementation, never the
+	// stored procedure.
+	ModeDirect
+)
+
+// dbCapability probes and caches whether a given *sql.DB is Postgres and
+// whether specific stored procedures exist on it. One instance is shared by
+// a provider (DatabaseAuthenticator, DatabaseTwoFactorProvider, etc.) across
+// all of its operations.
+type dbCapability struct {
+	funcExists sync.Map // procName (string) -> exists (bool)
+}
+
+// newDBCapability creates a new, empty capability cache.
+func newDBCapability() *dbCapability {
+	return &dbCapability{}
+}
+
+// reset clears all cached probe results. Call after reconnecting to a
+// (possibly different) database.
+func (c *dbCapability) reset() {
+	c.funcExists.Range(func(key, _ any) bool {
+		c.funcExists.Delete(key)
+		return true
+	})
+}
+
+// probeFunctionExists checks, via a Postgres-specific system catalog query,
+// whether a function named procName exists. Any error (wrong dialect,
+// placeholder syntax rejected, relation missing, etc.) is treated as "does
+// not exist" rather than propagated - the probe must never be able to panic
+// or block resolution of the query mode.
+func probeFunctionExists(ctx context.Context, db *sql.DB, procName string) bool {
+	if db == nil {
+		return false
+	}
+	var exists bool
+	defer func() {
+		// Guard against any unexpected panic from a misbehaving driver.
+		_ = recover()
+	}()
+	row := db.QueryRowContext(ctx, `SELECT EXISTS (SELECT 1 FROM pg_proc WHERE proname = $1 LIMIT 1)`, procName)
+	if err := row.Scan(&exists); err != nil {
+		return false
+	}
+	return exists
+}
+
+// ShouldUseProcedure decides whether the stored-procedure code path should be
+// used for procName given mode. ModeProcedure/ModeDirect are unconditional.
+//
+// ModeAuto resolves as follows:
+//   - A recognized portable-only driver (SQLite, MySQL) always uses Direct
+//     mode; no query is issued.
+//   - A recognized Postgres driver (lib/pq, pgx) probes pg_proc for procName
+//     and uses the stored procedure only if it actually exists there.
+//   - Any other/unrecognized driver (including test doubles such as
+//     sqlmock) cannot be safely dialect-probed without risking an
+//     unexpected query against a strictly-ordered mock, so it defaults to
+//     the stored-procedure path, preserving pre-existing behavior for
+//     callers that configure Postgres-flavored access without an
+//     identifiable driver type.
+func (c *dbCapability) ShouldUseProcedure(ctx context.Context, mode QueryMode, db *sql.DB, procName string) bool {
+	switch mode {
+	case ModeProcedure:
+		return true
+	case ModeDirect:
+		return false
+	default:
+		if cached, ok := c.funcExists.Load(procName); ok {
+			return cached.(bool)
+		}
+
+		var exists bool
+		switch {
+		case driverIsPortableOnly(db):
+			exists = false
+		case driverIsPostgres(db):
+			exists = probeFunctionExists(ctx, db, procName)
+		default:
+			exists = true
+		}
+
+		c.funcExists.Store(procName, exists)
+		return exists
+	}
+}
+
+// driverIsPostgres reports whether db's underlying driver looks like a
+// Postgres driver (lib/pq or pgx), based on the driver's Go type name.
+func driverIsPostgres(db *sql.DB) bool {
+	if db == nil {
+		return false
+	}
+	t := strings.ToLower(fmt.Sprintf("%T", db.Driver()))
+	return strings.Contains(t, "pq.") || strings.Contains(t, "pgx") || strings.Contains(t, "postgres")
+}
+
+// driverIsPortableOnly reports whether db's underlying driver is a dialect
+// that never has the resolvespec_* Postgres functions available (SQLite,
+// MySQL), so ModeAuto can skip probing entirely and go straight to Direct.
+func driverIsPortableOnly(db *sql.DB) bool {
+	if db == nil {
+		return false
+	}
+	t := strings.ToLower(fmt.Sprintf("%T", db.Driver()))
+	return strings.Contains(t, "sqlite") || strings.Contains(t, "mysql")
+}
+
+// rewritePlaceholders converts a query written with "?" placeholders
+// (SQLite/MySQL style) to Postgres "$1", "$2", ... style when db's driver is
+// Postgres. All Direct-mode SQL in this package is written with "?" and
+// passed through this helper before execution so the same query source works
+// against SQLite, MySQL, and (in the rare fallback case) Postgres without the
+// resolvespec_* functions installed.
+func rewritePlaceholders(db *sql.DB, query string) string {
+	if !driverIsPostgres(db) {
+		return query
+	}
+	var b strings.Builder
+	n := 0
+	for _, r := range query {
+		if r == '?' {
+			n++
+			b.WriteString("$")
+			b.WriteString(strconv.Itoa(n))
+		} else {
+			b.WriteRune(r)
+		}
+	}
+	return b.String()
+}
+
+// generateSessionToken produces a session token in the same shape the
+// plpgsql stored procedures generate: "sess_" + hex(32 random bytes) + "_" +
+// unix timestamp, so downstream code that parses/displays tokens is
+// unaffected by which mode created them.
+func generateSessionToken() (string, error) {
+	buf := make([]byte, 32)
+	if _, err := rand.Read(buf); err != nil {
+		return "", err
+	}
+	return fmt.Sprintf("sess_%s_%d", hex.EncodeToString(buf), time.Now().Unix()), nil
+}
diff --git a/pkg/security/query_mode_test.go b/pkg/security/query_mode_test.go
new file mode 100644
index 0000000..fdfe649
--- /dev/null
+++ b/pkg/security/query_mode_test.go
@@ -0,0 +1,165 @@
+package security
+
+import (
+	"context"
+	"database/sql"
+	"testing"
+
+	"github.com/DATA-DOG/go-sqlmock"
+	_ "github.com/mattn/go-sqlite3"
+)
+
+func openTestSQLite(t *testing.T) *sql.DB {
+	t.Helper()
+	db, err := sql.Open("sqlite3", ":memory:")
+	if err != nil {
+		t.Fatalf("failed to open sqlite db: %v", err)
+	}
+	t.Cleanup(func() { _ = db.Close() })
+	return db
+}
+
+func TestShouldUseProcedure_ModeProcedure_AlwaysTrue(t *testing.T) {
+	db := openTestSQLite(t)
+	c := newDBCapability()
+	if !c.ShouldUseProcedure(context.Background(), ModeProcedure, db, "resolvespec_login") {
+		t.Error("ModeProcedure should always resolve to true")
+	}
+}
+
+func TestShouldUseProcedure_ModeDirect_AlwaysFalse(t *testing.T) {
+	db := openTestSQLite(t)
+	c := newDBCapability()
+	if c.ShouldUseProcedure(context.Background(), ModeDirect, db, "resolvespec_login") {
+		t.Error("ModeDirect should always resolve to false")
+	}
+}
+
+func TestShouldUseProcedure_Auto_SQLite_ResolvesDirect(t *testing.T) {
+	db := openTestSQLite(t)
+	c := newDBCapability()
+	if c.ShouldUseProcedure(context.Background(), ModeAuto, db, "resolvespec_login") {
+		t.Error("ModeAuto against a SQLite connection should resolve to Direct (false)")
+	}
+}
+
+func TestShouldUseProcedure_Auto_UnknownDriver_DefaultsToProcedure(t *testing.T) {
+	db, mock, err := sqlmock.New()
+	if err != nil {
+		t.Fatalf("failed to create mock db: %v", err)
+	}
+	defer db.Close()
+
+	c := newDBCapability()
+	if !c.ShouldUseProcedure(context.Background(), ModeAuto, db, "resolvespec_login") {
+		t.Error("ModeAuto against an unrecognized driver (e.g. a test double) should default to Procedure (true) to preserve existing behavior")
+	}
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("unfulfilled expectations: %v", err)
+	}
+}
+
+func TestShouldUseProcedure_CachesResult(t *testing.T) {
+	db := openTestSQLite(t)
+	c := newDBCapability()
+	first := c.ShouldUseProcedure(context.Background(), ModeAuto, db, "resolvespec_login")
+	if _, ok := c.funcExists.Load("resolvespec_login"); !ok {
+		t.Error("expected result to be cached")
+	}
+	second := c.ShouldUseProcedure(context.Background(), ModeAuto, db, "resolvespec_login")
+	if first != second {
+		t.Errorf("cached result changed: first=%v second=%v", first, second)
+	}
+}
+
+func TestDBCapability_Reset_ClearsCache(t *testing.T) {
+	c := newDBCapability()
+	c.funcExists.Store("resolvespec_login", true)
+	c.reset()
+	if _, ok := c.funcExists.Load("resolvespec_login"); ok {
+		t.Error("reset should clear all cached entries")
+	}
+}
+
+func TestProbeFunctionExists_Postgres_FunctionExists(t *testing.T) {
+	db, mock, err := sqlmock.New()
+	if err != nil {
+		t.Fatalf("failed to create mock db: %v", err)
+	}
+	defer db.Close()
+
+	rows := sqlmock.NewRows([]string{"exists"}).AddRow(true)
+	mock.ExpectQuery(`SELECT EXISTS \(SELECT 1 FROM pg_proc WHERE proname = \$1 LIMIT 1\)`).
+		WithArgs("resolvespec_login").
+		WillReturnRows(rows)
+
+	if !probeFunctionExists(context.Background(), db, "resolvespec_login") {
+		t.Error("expected probeFunctionExists to return true")
+	}
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("unfulfilled expectations: %v", err)
+	}
+}
+
+func TestProbeFunctionExists_Postgres_FunctionMissing(t *testing.T) {
+	db, mock, err := sqlmock.New()
+	if err != nil {
+		t.Fatalf("failed to create mock db: %v", err)
+	}
+	defer db.Close()
+
+	rows := sqlmock.NewRows([]string{"exists"}).AddRow(false)
+	mock.ExpectQuery(`SELECT EXISTS \(SELECT 1 FROM pg_proc WHERE proname = \$1 LIMIT 1\)`).
+		WithArgs("resolvespec_login").
+		WillReturnRows(rows)
+
+	if probeFunctionExists(context.Background(), db, "resolvespec_login") {
+		t.Error("expected probeFunctionExists to return false")
+	}
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("unfulfilled expectations: %v", err)
+	}
+}
+
+func TestProbeFunctionExists_QueryError_ReturnsFalse(t *testing.T) {
+	db, mock, err := sqlmock.New()
+	if err != nil {
+		t.Fatalf("failed to create mock db: %v", err)
+	}
+	defer db.Close()
+
+	mock.ExpectQuery(`SELECT EXISTS \(SELECT 1 FROM pg_proc WHERE proname = \$1 LIMIT 1\)`).
+		WithArgs("resolvespec_login").
+		WillReturnError(sql.ErrConnDone)
+
+	if probeFunctionExists(context.Background(), db, "resolvespec_login") {
+		t.Error("expected probeFunctionExists to return false on query error")
+	}
+}
+
+func TestProbeFunctionExists_NilDB(t *testing.T) {
+	if probeFunctionExists(context.Background(), nil, "resolvespec_login") {
+		t.Error("expected probeFunctionExists(nil) to return false")
+	}
+}
+
+func TestRewritePlaceholders_NonPostgres_NoOp(t *testing.T) {
+	db := openTestSQLite(t)
+	q := "SELECT * FROM users WHERE id = ? AND name = ?"
+	if got := rewritePlaceholders(db, q); got != q {
+		t.Errorf("rewritePlaceholders on non-Postgres = %q, want unchanged %q", got, q)
+	}
+}
+
+func TestGenerateSessionToken_Format(t *testing.T) {
+	token, err := generateSessionToken()
+	if err != nil {
+		t.Fatalf("generateSessionToken() error = %v", err)
+	}
+	if len(token) < len("sess_")+64+2 {
+		t.Errorf("generateSessionToken() = %q, unexpected length", token)
+	}
+	if token[:5] != "sess_" {
+		t.Errorf("generateSessionToken() = %q, want prefix 'sess_'", token)
+	}
+}
diff --git a/pkg/security/table_names.go b/pkg/security/table_names.go
new file mode 100644
index 0000000..2a78d4c
--- /dev/null
+++ b/pkg/security/table_names.go
@@ -0,0 +1,101 @@
+package security
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+)
+
+// ErrDirectModeUnsupported is returned by Direct-mode operations that have no
+// portable equivalent because they depend on an external schema this package
+// does not own (e.g. core.secaccess / core.hub_link for column/row security).
+// Callers needing that functionality must run against Postgres with the
+// resolvespec_column_security / resolvespec_row_security stored procedures
+// installed (ModeProcedure or ModeAuto with the procedures present).
+var ErrDirectModeUnsupported = errors.New("direct mode does not support column/row security; requires the resolvespec_column_security/resolvespec_row_security stored procedures")
+
+// TableNames defines all configurable table names used by Direct-mode SQL
+// in the security package. Override individual fields to remap to custom
+// table names. Use DefaultTableNames() for baseline defaults, and
+// MergeTableNames() to apply partial overrides.
+type TableNames struct {
+	Users                  string // default: "users"
+	UserSessions           string // default: "user_sessions"
+	TokenBlacklist         string // default: "token_blacklist"
+	UserTOTPBackupCodes    string // default: "user_totp_backup_codes"
+	UserPasskeyCredentials string // default: "user_passkey_credentials"
+	UserPasswordResets     string // default: "user_password_resets"
+	OAuthClients           string // default: "oauth_clients"
+	OAuthCodes             string // default: "oauth_codes"
+}
+
+// DefaultTableNames returns a TableNames with all default table names.
+func DefaultTableNames() *TableNames {
+	return &TableNames{
+		Users:                  "users",
+		UserSessions:           "user_sessions",
+		TokenBlacklist:         "token_blacklist",
+		UserTOTPBackupCodes:    "user_totp_backup_codes",
+		UserPasskeyCredentials: "user_passkey_credentials",
+		UserPasswordResets:     "user_password_resets",
+		OAuthClients:           "oauth_clients",
+		OAuthCodes:             "oauth_codes",
+	}
+}
+
+// MergeTableNames returns a copy of base with any non-empty fields from override applied.
+// If override is nil, a copy of base is returned.
+func MergeTableNames(base, override *TableNames) *TableNames {
+	if override == nil {
+		copied := *base
+		return &copied
+	}
+	merged := *base
+	if override.Users != "" {
+		merged.Users = override.Users
+	}
+	if override.UserSessions != "" {
+		merged.UserSessions = override.UserSessions
+	}
+	if override.TokenBlacklist != "" {
+		merged.TokenBlacklist = override.TokenBlacklist
+	}
+	if override.UserTOTPBackupCodes != "" {
+		merged.UserTOTPBackupCodes = override.UserTOTPBackupCodes
+	}
+	if override.UserPasskeyCredentials != "" {
+		merged.UserPasskeyCredentials = override.UserPasskeyCredentials
+	}
+	if override.UserPasswordResets != "" {
+		merged.UserPasswordResets = override.UserPasswordResets
+	}
+	if override.OAuthClients != "" {
+		merged.OAuthClients = override.OAuthClients
+	}
+	if override.OAuthCodes != "" {
+		merged.OAuthCodes = override.OAuthCodes
+	}
+	return &merged
+}
+
+// ValidateTableNames checks that all non-empty fields in names are valid SQL identifiers.
+func ValidateTableNames(names *TableNames) error {
+	v := reflect.ValueOf(names).Elem()
+	typ := v.Type()
+	for i := 0; i < v.NumField(); i++ {
+		field := v.Field(i)
+		if field.Kind() != reflect.String {
+			continue
+		}
+		val := field.String()
+		if val != "" && !validSQLIdentifier.MatchString(val) {
+			return fmt.Errorf("TableNames.%s contains invalid characters: %q", typ.Field(i).Name, val)
+		}
+	}
+	return nil
+}
+
+// resolveTableNames merges an optional override with defaults.
+func resolveTableNames(override *TableNames) *TableNames {
+	return MergeTableNames(DefaultTableNames(), override)
+}
diff --git a/pkg/security/table_names_test.go b/pkg/security/table_names_test.go
new file mode 100644
index 0000000..3990a06
--- /dev/null
+++ b/pkg/security/table_names_test.go
@@ -0,0 +1,134 @@
+package security
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestDefaultTableNames_AllFieldsNonEmpty(t *testing.T) {
+	names := DefaultTableNames()
+	v := reflect.ValueOf(names).Elem()
+	typ := v.Type()
+
+	for i := 0; i < v.NumField(); i++ {
+		field := v.Field(i)
+		if field.Kind() != reflect.String {
+			continue
+		}
+		if field.String() == "" {
+			t.Errorf("DefaultTableNames().%s is empty", typ.Field(i).Name)
+		}
+	}
+}
+
+func TestMergeTableNames_PartialOverride(t *testing.T) {
+	base := DefaultTableNames()
+	override := &TableNames{Users: "custom_users", OAuthCodes: "custom_oauth_codes"}
+
+	merged := MergeTableNames(base, override)
+
+	if merged.Users != "custom_users" {
+		t.Errorf("MergeTableNames().Users = %q, want %q", merged.Users, "custom_users")
+	}
+	if merged.OAuthCodes != "custom_oauth_codes" {
+		t.Errorf("MergeTableNames().OAuthCodes = %q, want %q", merged.OAuthCodes, "custom_oauth_codes")
+	}
+	if merged.UserSessions != "user_sessions" {
+		t.Errorf("MergeTableNames().UserSessions = %q, want default", merged.UserSessions)
+	}
+}
+
+func TestMergeTableNames_NilOverride(t *testing.T) {
+	base := DefaultTableNames()
+	merged := MergeTableNames(base, nil)
+
+	if merged == base {
+		t.Error("MergeTableNames with nil override should return a copy, not the same pointer")
+	}
+	if *merged != *base {
+		t.Errorf("MergeTableNames(base, nil) = %+v, want %+v", merged, base)
+	}
+}
+
+func TestMergeTableNames_DoesNotMutateBase(t *testing.T) {
+	base := DefaultTableNames()
+	original := base.Users
+
+	override := &TableNames{Users: "custom_users"}
+	_ = MergeTableNames(base, override)
+
+	if base.Users != original {
+		t.Errorf("MergeTableNames mutated base: Users = %q, want %q", base.Users, original)
+	}
+}
+
+func TestValidateTableNames_Valid(t *testing.T) {
+	if err := ValidateTableNames(DefaultTableNames()); err != nil {
+		t.Errorf("ValidateTableNames(defaults) error = %v", err)
+	}
+}
+
+func TestValidateTableNames_Invalid(t *testing.T) {
+	names := DefaultTableNames()
+	names.Users = "users; DROP TABLE users; --"
+
+	if err := ValidateTableNames(names); err == nil {
+		t.Error("ValidateTableNames should reject names with invalid characters")
+	}
+}
+
+func TestResolveTableNames_NoOverride(t *testing.T) {
+	names := resolveTableNames(nil)
+	if names.Users != "users" {
+		t.Errorf("resolveTableNames(nil).Users = %q, want default", names.Users)
+	}
+}
+
+func TestResolveTableNames_WithOverride(t *testing.T) {
+	names := resolveTableNames(&TableNames{Users: "custom_users"})
+	if names.Users != "custom_users" {
+		t.Errorf("resolveTableNames().Users = %q, want %q", names.Users, "custom_users")
+	}
+	if names.UserSessions != "user_sessions" {
+		t.Errorf("resolveTableNames().UserSessions = %q, want default", names.UserSessions)
+	}
+}
+
+func TestDefaultKeyStoreTableNames(t *testing.T) {
+	names := DefaultKeyStoreTableNames()
+	if names.UserKeys != "user_keys" {
+		t.Errorf("DefaultKeyStoreTableNames().UserKeys = %q, want %q", names.UserKeys, "user_keys")
+	}
+}
+
+func TestMergeKeyStoreTableNames_PartialOverride(t *testing.T) {
+	base := DefaultKeyStoreTableNames()
+	merged := MergeKeyStoreTableNames(base, &KeyStoreTableNames{UserKeys: "custom_keys"})
+	if merged.UserKeys != "custom_keys" {
+		t.Errorf("MergeKeyStoreTableNames().UserKeys = %q, want %q", merged.UserKeys, "custom_keys")
+	}
+}
+
+func TestMergeKeyStoreTableNames_NilOverride(t *testing.T) {
+	base := DefaultKeyStoreTableNames()
+	merged := MergeKeyStoreTableNames(base, nil)
+	if merged == base {
+		t.Error("MergeKeyStoreTableNames with nil override should return a copy, not the same pointer")
+	}
+	if *merged != *base {
+		t.Errorf("MergeKeyStoreTableNames(base, nil) = %+v, want %+v", merged, base)
+	}
+}
+
+func TestValidateKeyStoreTableNames_Invalid(t *testing.T) {
+	names := &KeyStoreTableNames{UserKeys: "bad name!"}
+	if err := ValidateKeyStoreTableNames(names); err == nil {
+		t.Error("ValidateKeyStoreTableNames should reject names with invalid characters")
+	}
+}
+
+func TestValidateKeyStoreTableNames_Valid(t *testing.T) {
+	if err := ValidateKeyStoreTableNames(DefaultKeyStoreTableNames()); err != nil {
+		t.Errorf("ValidateKeyStoreTableNames(defaults) error = %v", err)
+	}
+}
diff --git a/pkg/security/totp_provider_database.go b/pkg/security/totp_provider_database.go
index 6fe8c5e..17c306d 100644
--- a/pkg/security/totp_provider_database.go
+++ b/pkg/security/totp_provider_database.go
@@ -1,20 +1,27 @@
 package security
 
 import (
+	"context"
 	"crypto/sha256"
 	"database/sql"
 	"encoding/hex"
 	"encoding/json"
 	"fmt"
+	"sync"
 )
 
 // DatabaseTwoFactorProvider implements TwoFactorAuthProvider using PostgreSQL stored procedures
 // Procedure names are configurable via SQLNames (see DefaultSQLNames for defaults)
 // See totp_database_schema.sql for procedure definitions
 type DatabaseTwoFactorProvider struct {
-	db       *sql.DB
-	totpGen  *TOTPGenerator
-	sqlNames *SQLNames
+	db         *sql.DB
+	dbMu       sync.RWMutex
+	dbFactory  func() (*sql.DB, error)
+	totpGen    *TOTPGenerator
+	sqlNames   *SQLNames
+	tableNames *TableNames
+	queryMode  QueryMode
+	capability *dbCapability
 }
 
 // NewDatabaseTwoFactorProvider creates a new database-backed 2FA provider
@@ -23,12 +30,69 @@ func NewDatabaseTwoFactorProvider(db *sql.DB, config *TwoFactorConfig, names ...
 		config = DefaultTwoFactorConfig()
 	}
 	return &DatabaseTwoFactorProvider{
-		db:       db,
-		totpGen:  NewTOTPGenerator(config),
-		sqlNames: resolveSQLNames(names...),
+		db:         db,
+		totpGen:    NewTOTPGenerator(config),
+		sqlNames:   resolveSQLNames(names...),
+		tableNames: DefaultTableNames(),
+		capability: newDBCapability(),
 	}
 }
 
+// WithDBFactory configures a factory used to reopen the database connection if it is closed.
+func (p *DatabaseTwoFactorProvider) WithDBFactory(factory func() (*sql.DB, error)) *DatabaseTwoFactorProvider {
+	p.dbFactory = factory
+	return p
+}
+
+// WithTableNames configures Direct-mode table names. If names is nil, defaults are used.
+func (p *DatabaseTwoFactorProvider) WithTableNames(names *TableNames) *DatabaseTwoFactorProvider {
+	p.tableNames = resolveTableNames(names)
+	return p
+}
+
+// WithQueryMode selects stored-procedure vs Direct-mode SQL (default ModeAuto).
+func (p *DatabaseTwoFactorProvider) WithQueryMode(mode QueryMode) *DatabaseTwoFactorProvider {
+	p.queryMode = mode
+	return p
+}
+
+func (p *DatabaseTwoFactorProvider) getDB() *sql.DB {
+	p.dbMu.RLock()
+	defer p.dbMu.RUnlock()
+	return p.db
+}
+
+func (p *DatabaseTwoFactorProvider) reconnectDB() error {
+	if p.dbFactory == nil {
+		return fmt.Errorf("no db factory configured for reconnect")
+	}
+	newDB, err := p.dbFactory()
+	if err != nil {
+		return err
+	}
+	p.dbMu.Lock()
+	p.db = newDB
+	p.dbMu.Unlock()
+	if p.capability != nil {
+		p.capability.reset()
+	}
+	return nil
+}
+
+func (p *DatabaseTwoFactorProvider) runDBOpWithReconnect(run func(*sql.DB) error) error {
+	db := p.getDB()
+	if db == nil {
+		return fmt.Errorf("database connection is nil")
+	}
+	err := run(db)
+	if isDBClosed(err) {
+		if reconnErr := p.reconnectDB(); reconnErr == nil {
+			err = run(p.getDB())
+		}
+	}
+	return err
+}
+
 // Generate2FASecret creates a new secret for a user
 func (p *DatabaseTwoFactorProvider) Generate2FASecret(userID int, issuer, accountName string) (*TwoFactorSecret, error) {
 	secret, err := p.totpGen.GenerateSecret()
@@ -72,12 +136,17 @@ func (p *DatabaseTwoFactorProvider) Enable2FA(userID int, secret string, backupC
 		return fmt.Errorf("failed to marshal backup codes: %w", err)
 	}
 
+	ctx := context.Background()
+	if !p.capability.ShouldUseProcedure(ctx, p.queryMode, p.getDB(), p.sqlNames.TOTPEnable) {
+		return p.enable2FADirect(ctx, userID, secret, hashedCodes)
+	}
+
 	// Call stored procedure
 	var success bool
 	var errorMsg sql.NullString
 
 	query := fmt.Sprintf(`SELECT p_success, p_error FROM %s($1, $2, $3::jsonb)`, p.sqlNames.TOTPEnable)
-	err = p.db.QueryRow(query, userID, secret, string(codesJSON)).Scan(&success, &errorMsg)
+	err = p.getDB().QueryRow(query, userID, secret, string(codesJSON)).Scan(&success, &errorMsg)
 	if err != nil {
 		return fmt.Errorf("enable 2FA query failed: %w", err)
 	}
@@ -94,11 +163,16 @@ func (p *DatabaseTwoFactorProvider) Enable2FA(userID int, secret string, backupC
 
 // Disable2FA deactivates 2FA for a user
 func (p *DatabaseTwoFactorProvider) Disable2FA(userID int) error {
+	ctx := context.Background()
+	if !p.capability.ShouldUseProcedure(ctx, p.queryMode, p.getDB(), p.sqlNames.TOTPDisable) {
+		return p.disable2FADirect(ctx, userID)
+	}
+
 	var success bool
 	var errorMsg sql.NullString
 
 	query := fmt.Sprintf(`SELECT p_success, p_error FROM %s($1)`, p.sqlNames.TOTPDisable)
-	err := p.db.QueryRow(query, userID).Scan(&success, &errorMsg)
+	err := p.getDB().QueryRow(query, userID).Scan(&success, &errorMsg)
 	if err != nil {
 		return fmt.Errorf("disable 2FA query failed: %w", err)
 	}
@@ -115,12 +189,17 @@ func (p *DatabaseTwoFactorProvider) Disable2FA(userID int) error {
 
 // Get2FAStatus checks if user has 2FA enabled
 func (p *DatabaseTwoFactorProvider) Get2FAStatus(userID int) (bool, error) {
+	ctx := context.Background()
+	if !p.capability.ShouldUseProcedure(ctx, p.queryMode, p.getDB(), p.sqlNames.TOTPGetStatus) {
+		return p.get2FAStatusDirect(ctx, userID)
+	}
+
 	var success bool
 	var errorMsg sql.NullString
 	var enabled bool
 
 	query := fmt.Sprintf(`SELECT p_success, p_error, p_enabled FROM %s($1)`, p.sqlNames.TOTPGetStatus)
-	err := p.db.QueryRow(query, userID).Scan(&success, &errorMsg, &enabled)
+	err := p.getDB().QueryRow(query, userID).Scan(&success, &errorMsg, &enabled)
 	if err != nil {
 		return false, fmt.Errorf("get 2FA status query failed: %w", err)
 	}
@@ -137,12 +216,17 @@ func (p *DatabaseTwoFactorProvider) Get2FAStatus(userID int) (bool, error) {
 
 // Get2FASecret retrieves the user's 2FA secret
 func (p *DatabaseTwoFactorProvider) Get2FASecret(userID int) (string, error) {
+	ctx := context.Background()
+	if !p.capability.ShouldUseProcedure(ctx, p.queryMode, p.getDB(), p.sqlNames.TOTPGetSecret) {
+		return p.get2FASecretDirect(ctx, userID)
+	}
+
 	var success bool
 	var errorMsg sql.NullString
 	var secret sql.NullString
 
 	query := fmt.Sprintf(`SELECT p_success, p_error, p_secret FROM %s($1)`, p.sqlNames.TOTPGetSecret)
-	err := p.db.QueryRow(query, userID).Scan(&success, &errorMsg, &secret)
+	err := p.getDB().QueryRow(query, userID).Scan(&success, &errorMsg, &secret)
 	if err != nil {
 		return "", fmt.Errorf("get 2FA secret query failed: %w", err)
 	}
@@ -175,6 +259,14 @@ func (p *DatabaseTwoFactorProvider) GenerateBackupCodes(userID int, count int) (
 		hashedCodes[i] = hex.EncodeToString(hash[:])
 	}
 
+	ctx := context.Background()
+	if !p.capability.ShouldUseProcedure(ctx, p.queryMode, p.getDB(), p.sqlNames.TOTPRegenerateBackup) {
+		if err := p.regenerateBackupCodesDirect(ctx, userID, hashedCodes); err != nil {
+			return nil, err
+		}
+		return codes, nil
+	}
+
 	// Convert to JSON array
 	codesJSON, err := json.Marshal(hashedCodes)
 	if err != nil {
@@ -186,7 +278,7 @@ func (p *DatabaseTwoFactorProvider) GenerateBackupCodes(userID int, count int) (
 	var errorMsg sql.NullString
 
 	query := fmt.Sprintf(`SELECT p_success, p_error FROM %s($1, $2::jsonb)`, p.sqlNames.TOTPRegenerateBackup)
-	err = p.db.QueryRow(query, userID, string(codesJSON)).Scan(&success, &errorMsg)
+	err = p.getDB().QueryRow(query, userID, string(codesJSON)).Scan(&success, &errorMsg)
 	if err != nil {
 		return nil, fmt.Errorf("regenerate backup codes query failed: %w", err)
 	}
@@ -208,12 +300,17 @@ func (p *DatabaseTwoFactorProvider) ValidateBackupCode(userID int, code string)
 	hash := sha256.Sum256([]byte(code))
 	codeHash := hex.EncodeToString(hash[:])
 
+	ctx := context.Background()
+	if !p.capability.ShouldUseProcedure(ctx, p.queryMode, p.getDB(), p.sqlNames.TOTPValidateBackupCode) {
+		return p.validateBackupCodeDirect(ctx, userID, codeHash)
+	}
+
 	var success bool
 	var errorMsg sql.NullString
 	var valid bool
 
 	query := fmt.Sprintf(`SELECT p_success, p_error, p_valid FROM %s($1, $2)`, p.sqlNames.TOTPValidateBackupCode)
-	err := p.db.QueryRow(query, userID, codeHash).Scan(&success, &errorMsg, &valid)
+	err := p.getDB().QueryRow(query, userID, codeHash).Scan(&success, &errorMsg, &valid)
 	if err != nil {
 		return false, fmt.Errorf("validate backup code query failed: %w", err)
 	}
diff --git a/pkg/security/totp_provider_database_direct.go b/pkg/security/totp_provider_database_direct.go
new file mode 100644
index 0000000..9055cd4
--- /dev/null
+++ b/pkg/security/totp_provider_database_direct.go
@@ -0,0 +1,151 @@
+package security
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"fmt"
+	"time"
+)
+
+// Direct-mode implementations mirroring the resolvespec_totp_* stored
+// procedures in database_schema.sql using plain SQL against TableNames.
+
+func (p *DatabaseTwoFactorProvider) enable2FADirect(ctx context.Context, userID int, secret string, hashedCodes []string) error {
+	return p.runDBOpWithReconnect(func(db *sql.DB) error {
+		updQuery := rewritePlaceholders(db, fmt.Sprintf(
+			`UPDATE %s SET totp_secret = ?, totp_enabled = ?, totp_enabled_at = ? WHERE id = ?`, p.tableNames.Users))
+		res, err := db.ExecContext(ctx, updQuery, secret, true, time.Now(), userID)
+		if err != nil {
+			return err
+		}
+		if rows, err := res.RowsAffected(); err != nil {
+			return err
+		} else if rows == 0 {
+			return fmt.Errorf("User not found")
+		}
+
+		delQuery := rewritePlaceholders(db, fmt.Sprintf(`DELETE FROM %s WHERE user_id = ?`, p.tableNames.UserTOTPBackupCodes))
+		if _, err := db.ExecContext(ctx, delQuery, userID); err != nil {
+			return err
+		}
+
+		insQuery := rewritePlaceholders(db, fmt.Sprintf(`INSERT INTO %s (user_id, code_hash) VALUES (?, ?)`, p.tableNames.UserTOTPBackupCodes))
+		for _, hash := range hashedCodes {
+			if _, err := db.ExecContext(ctx, insQuery, userID, hash); err != nil {
+				return err
+			}
+		}
+		return nil
+	})
+}
+
+func (p *DatabaseTwoFactorProvider) disable2FADirect(ctx context.Context, userID int) error {
+	return p.runDBOpWithReconnect(func(db *sql.DB) error {
+		updQuery := rewritePlaceholders(db, fmt.Sprintf(`UPDATE %s SET totp_secret = NULL, totp_enabled = ? WHERE id = ?`, p.tableNames.Users))
+		res, err := db.ExecContext(ctx, updQuery, false, userID)
+		if err != nil {
+			return err
+		}
+		if rows, err := res.RowsAffected(); err != nil {
+			return err
+		} else if rows == 0 {
+			return fmt.Errorf("User not found")
+		}
+
+		delQuery := rewritePlaceholders(db, fmt.Sprintf(`DELETE FROM %s WHERE user_id = ?`, p.tableNames.UserTOTPBackupCodes))
+		_, err = db.ExecContext(ctx, delQuery, userID)
+		return err
+	})
+}
+
+func (p *DatabaseTwoFactorProvider) get2FAStatusDirect(ctx context.Context, userID int) (bool, error) {
+	var enabled sql.NullBool
+	err := p.runDBOpWithReconnect(func(db *sql.DB) error {
+		query := rewritePlaceholders(db, fmt.Sprintf(`SELECT totp_enabled FROM %s WHERE id = ?`, p.tableNames.Users))
+		return db.QueryRowContext(ctx, query, userID).Scan(&enabled)
+	})
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return false, fmt.Errorf("User not found")
+		}
+		return false, fmt.Errorf("get 2FA status query failed: %w", err)
+	}
+	return enabled.Bool, nil
+}
+
+func (p *DatabaseTwoFactorProvider) get2FASecretDirect(ctx context.Context, userID int) (string, error) {
+	var secret sql.NullString
+	var enabled sql.NullBool
+	err := p.runDBOpWithReconnect(func(db *sql.DB) error {
+		query := rewritePlaceholders(db, fmt.Sprintf(`SELECT totp_secret, totp_enabled FROM %s WHERE id = ?`, p.tableNames.Users))
+		return db.QueryRowContext(ctx, query, userID).Scan(&secret, &enabled)
+	})
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return "", fmt.Errorf("User not found")
+		}
+		return "", fmt.Errorf("get 2FA secret query failed: %w", err)
+	}
+	if !enabled.Bool {
+		return "", fmt.Errorf("TOTP not enabled for user")
+	}
+	return secret.String, nil
+}
+
+func (p *DatabaseTwoFactorProvider) regenerateBackupCodesDirect(ctx context.Context, userID int, hashedCodes []string) error {
+	return p.runDBOpWithReconnect(func(db *sql.DB) error {
+		var count int
+		checkQuery := rewritePlaceholders(db, fmt.Sprintf(`SELECT COUNT(*) FROM %s WHERE id = ? AND totp_enabled = ?`, p.tableNames.Users))
+		if err := db.QueryRowContext(ctx, checkQuery, userID, true).Scan(&count); err != nil {
+			return err
+		}
+		if count == 0 {
+			return fmt.Errorf("User not found or TOTP not enabled")
+		}
+
+		delQuery := rewritePlaceholders(db, fmt.Sprintf(`DELETE FROM %s WHERE user_id = ?`, p.tableNames.UserTOTPBackupCodes))
+		if _, err := db.ExecContext(ctx, delQuery, userID); err != nil {
+			return err
+		}
+
+		insQuery := rewritePlaceholders(db, fmt.Sprintf(`INSERT INTO %s (user_id, code_hash) VALUES (?, ?)`, p.tableNames.UserTOTPBackupCodes))
+		for _, hash := range hashedCodes {
+			if _, err := db.ExecContext(ctx, insQuery, userID, hash); err != nil {
+				return err
+			}
+		}
+		return nil
+	})
+}
+
+func (p *DatabaseTwoFactorProvider) validateBackupCodeDirect(ctx context.Context, userID int, codeHash string) (bool, error) {
+	var valid bool
+	err := p.runDBOpWithReconnect(func(db *sql.DB) error {
+		var codeID int
+		var used bool
+		query := rewritePlaceholders(db, fmt.Sprintf(`SELECT id, used FROM %s WHERE user_id = ? AND code_hash = ?`, p.tableNames.UserTOTPBackupCodes))
+		err := db.QueryRowContext(ctx, query, userID, codeHash).Scan(&codeID, &used)
+		if errors.Is(err, sql.ErrNoRows) {
+			valid = false
+			return nil
+		}
+		if err != nil {
+			return err
+		}
+		if used {
+			return fmt.Errorf("Backup code already used")
+		}
+
+		updQuery := rewritePlaceholders(db, fmt.Sprintf(`UPDATE %s SET used = ?, used_at = ? WHERE id = ?`, p.tableNames.UserTOTPBackupCodes))
+		if _, err := db.ExecContext(ctx, updQuery, true, time.Now(), codeID); err != nil {
+			return err
+		}
+		valid = true
+		return nil
+	})
+	if err != nil {
+		return false, err
+	}
+	return valid, nil
+}