feat(transport): add streamable HTTP transport for MCP

* Add security hooks for per-entity operation rules and row/column-level security.
* Implement annotation tool for storing and retrieving freeform annotations.
* Enhance handler to support model registration with access rules.

go.mod

@@ -15,6 +15,7 @@ require (
 	github.com/gorilla/websocket v1.5.3
 	github.com/jackc/pgx/v5 v5.8.0
 	github.com/klauspost/compress v1.18.2
+	github.com/mark3labs/mcp-go v0.46.0
 	github.com/mattn/go-sqlite3 v1.14.33
 	github.com/microsoft/go-mssqldb v1.9.5
 	github.com/mochi-mqtt/server/v2 v2.7.9
@@ -88,7 +89,6 @@ require (
 	github.com/jinzhu/now v1.1.5 // indirect
 	github.com/lufia/plan9stats v0.0.0-20211012122336-39d0f177ccd0 // indirect
 	github.com/magiconair/properties v1.8.10 // indirect
-	github.com/mark3labs/mcp-go v0.46.0 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
 	github.com/moby/docker-image-spec v1.3.1 // indirect
 	github.com/moby/go-archive v0.1.0 // indirect

pkg/dbmanager/connection.go

@@ -26,6 +26,7 @@ type Connection interface {
 	Bun() (*bun.DB, error)
 	GORM() (*gorm.DB, error)
 	Native() (*sql.DB, error)
+	DB() (*sql.DB, error)
 
 	// Common Database interface (for SQL databases)
 	Database() (common.Database, error)
@@ -224,6 +225,11 @@ func (c *sqlConnection) Native() (*sql.DB, error) {
 	return c.nativeDB, nil
 }
 
+// DB returns the underlying *sql.DB connection
+func (c *sqlConnection) DB() (*sql.DB, error) {
+	return c.Native()
+}
+
 // Bun returns a Bun ORM instance wrapping the native connection
 func (c *sqlConnection) Bun() (*bun.DB, error) {
 	if c == nil {
@@ -645,6 +651,11 @@ func (c *mongoConnection) Native() (*sql.DB, error) {
 	return nil, ErrNotSQLDatabase
 }
 
+// DB returns an error for MongoDB connections
+func (c *mongoConnection) DB() (*sql.DB, error) {
+	return nil, ErrNotSQLDatabase
+}
+
 // Database returns an error for MongoDB connections
 func (c *mongoConnection) Database() (common.Database, error) {
 	return nil, ErrNotSQLDatabase

pkg/resolvemcp/README.md

@@ -67,58 +67,164 @@ Each call immediately creates four MCP **tools** and one MCP **resource** for th
 
 ---
 
-## HTTP / SSE Transport
+## HTTP Transports
-
-The `*server.SSEServer` returned by any of the helpers below implements `http.Handler`, so it works with every Go HTTP framework.
 
 `Config.BasePath` is required and used for all route registration.
 `Config.BaseURL` is optional — when empty it is detected from each request.
 
-### Gorilla Mux
+Two transports are supported: **SSE** (legacy, two-endpoint) and **Streamable HTTP** (recommended, single-endpoint).
+
+---
+
+### SSE Transport
+
+Two endpoints: `GET {BasePath}/sse` (subscribe) + `POST {BasePath}/message` (send).
+
+#### Gorilla Mux
 
 ```go
 resolvemcp.SetupMuxRoutes(r, handler)
 ```
 
-Registers:
-
 | Route | Method | Description |
 |---|---|---|
 | `{BasePath}/sse` | GET | SSE connection — clients subscribe here |
 | `{BasePath}/message` | POST | JSON-RPC — clients send requests here |
-| `{BasePath}/*` | any | Full SSE server (convenience prefix) |
 
-### bunrouter
+#### bunrouter
 
 ```go
 resolvemcp.SetupBunRouterRoutes(router, handler)
 ```
 
-Registers `GET {BasePath}/sse` and `POST {BasePath}/message` on the provided `*bunrouter.Router`.
+#### Gin / net/http / Echo
-
-### Gin (or any `http.Handler`-compatible framework)
-
-Use `handler.SSEServer()` to get an `http.Handler` and wrap it with the framework's adapter:
 
 ```go
 sse := handler.SSEServer()
 
-// Gin
+engine.Any("/mcp/*path", gin.WrapH(sse))  // Gin
-engine.Any("/mcp/*path", gin.WrapH(sse))
+http.Handle("/mcp/", sse)                  // net/http
-
+e.Any("/mcp/*", echo.WrapHandler(sse))     // Echo
-// net/http
-http.Handle("/mcp/", sse)
-
-// Echo
-e.Any("/mcp/*", echo.WrapHandler(sse))
 ```
 
+---
+
+### Streamable HTTP Transport
+
+Single endpoint at `{BasePath}`. Handles POST (client→server) and GET (server→client streaming). Preferred for new integrations.
+
+#### Gorilla Mux
+
+```go
+resolvemcp.SetupMuxStreamableHTTPRoutes(r, handler)
+```
+
+Mounts the handler at `{BasePath}` (all methods).
+
+#### bunrouter
+
+```go
+resolvemcp.SetupBunRouterStreamableHTTPRoutes(router, handler)
+```
+
+Registers GET, POST, DELETE on `{BasePath}`.
+
+#### Gin / net/http / Echo
+
+```go
+h := handler.StreamableHTTPServer()
+// or: h := resolvemcp.NewStreamableHTTPHandler(handler)
+
+engine.Any("/mcp", gin.WrapH(h))      // Gin
+http.Handle("/mcp", h)                 // net/http
+e.Any("/mcp", echo.WrapHandler(h))     // Echo
+```
+
+---
+
 ### Authentication
 
 Add middleware before the MCP routes. The handler itself has no auth layer.
 
 ---
 
+## Security
+
+`resolvemcp` integrates with the `security` package to provide per-entity access control, row-level security, and column-level security — the same system used by `resolvespec` and `restheadspec`.
+
+### Wiring security hooks
+
+```go
+import "github.com/bitechdev/ResolveSpec/pkg/security"
+
+securityList := security.NewSecurityList(mySecurityProvider)
+resolvemcp.RegisterSecurityHooks(handler, securityList)
+```
+
+Call `RegisterSecurityHooks` **once**, after creating the handler and before registering models. It installs these controls automatically:
+
+| Hook | Effect |
+|---|---|
+| `BeforeHandle` | Enforces per-entity operation rules (see below) |
+| `BeforeRead` | Loads RLS/CLS rules, then injects a user-scoped WHERE clause |
+| `AfterRead` | Masks/hides columns per column-security rules; writes audit log |
+| `BeforeUpdate` | Blocks update if `CanUpdate` is false |
+| `BeforeDelete` | Blocks delete if `CanDelete` is false |
+
+### Per-entity operation rules
+
+Use `RegisterModelWithRules` instead of `RegisterModel` to set access rules at registration time:
+
+```go
+import "github.com/bitechdev/ResolveSpec/pkg/modelregistry"
+
+// Read-only entity
+handler.RegisterModelWithRules("public", "audit_logs", &AuditLog{}, modelregistry.ModelRules{
+    CanRead:   true,
+    CanCreate: false,
+    CanUpdate: false,
+    CanDelete: false,
+})
+
+// Public read, authenticated write
+handler.RegisterModelWithRules("public", "products", &Product{}, modelregistry.ModelRules{
+    CanPublicRead: true,
+    CanRead:       true,
+    CanCreate:     true,
+    CanUpdate:     true,
+    CanDelete:     false,
+})
+```
+
+To update rules for an already-registered model:
+
+```go
+handler.SetModelRules("public", "users", modelregistry.ModelRules{
+    CanRead:   true,
+    CanCreate: true,
+    CanUpdate: true,
+    CanDelete: false,
+})
+```
+
+`RegisterModel` (no rules) registers with all-allowed defaults (`CanRead/Create/Update/Delete = true`).
+
+### ModelRules fields
+
+| Field | Default | Description |
+|---|---|---|
+| `CanPublicRead` | `false` | Allow unauthenticated reads |
+| `CanPublicCreate` | `false` | Allow unauthenticated creates |
+| `CanPublicUpdate` | `false` | Allow unauthenticated updates |
+| `CanPublicDelete` | `false` | Allow unauthenticated deletes |
+| `CanRead` | `true` | Allow authenticated reads |
+| `CanCreate` | `true` | Allow authenticated creates |
+| `CanUpdate` | `true` | Allow authenticated updates |
+| `CanDelete` | `true` | Allow authenticated deletes |
+| `SecurityDisabled` | `false` | Skip all security checks for this model |
+
+---
+
 ## MCP Tools
 
 ### Tool Naming
@@ -204,6 +310,35 @@ Delete a record by primary key. **Irreversible.**
 { "success": true, "data": { ...deleted record... } }
 ```
 
+### Annotation Tool — `resolvespec_annotate`
+
+Store or retrieve freeform annotation records for any tool, model, or entity. Registered automatically on every handler.
+
+| Argument | Type | Description |
+|---|---|---|
+| `tool_name` | string (required) | Key to annotate — an MCP tool name (e.g. `read_public_users`), a model name (e.g. `public.users`), or any other identifier. |
+| `annotations` | object | Annotation data to persist. Omit to retrieve existing annotations instead. |
+
+**Set annotations** (calls `resolvespec_set_annotation(tool_name, annotations)`):
+```json
+{ "tool_name": "read_public_users", "annotations": { "description": "Returns active users", "owner": "platform-team" } }
+```
+**Response:**
+```json
+{ "success": true, "tool_name": "read_public_users", "action": "set" }
+```
+
+**Get annotations** (calls `resolvespec_get_annotation(tool_name)`):
+```json
+{ "tool_name": "read_public_users" }
+```
+**Response:**
+```json
+{ "success": true, "tool_name": "read_public_users", "action": "get", "annotations": { ... } }
+```
+
+---
+
 ### Resource — `{schema}.{entity}`
 
 Each model is also registered as an MCP resource with URI `schema.entity` (or just `entity` when schema is empty). Reading the resource returns up to 100 records as `application/json`.

pkg/resolvemcp/annotation.go

@@ -0,0 +1,107 @@
+package resolvemcp
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+
+	"github.com/mark3labs/mcp-go/mcp"
+)
+
+const annotationToolName = "resolvespec_annotate"
+
+// registerAnnotationTool adds the resolvespec_annotate tool to the MCP server.
+// The tool lets models/entities store and retrieve freeform annotation records
+// using the resolvespec_set_annotation / resolvespec_get_annotation database procedures.
+func registerAnnotationTool(h *Handler) {
+	tool := mcp.NewTool(annotationToolName,
+		mcp.WithDescription(
+			"Store or retrieve annotations for any MCP tool, model, or entity.\n\n"+
+				"To set annotations: provide both 'tool_name' and 'annotations'. "+
+				"Calls resolvespec_set_annotation(tool_name, annotations) to persist the data.\n\n"+
+				"To get annotations: provide only 'tool_name'. "+
+				"Calls resolvespec_get_annotation(tool_name) and returns the stored annotations.\n\n"+
+				"'tool_name' may be any identifier: an MCP tool name (e.g. 'read_public_users'), "+
+				"a model/entity name (e.g. 'public.users'), or any other key.",
+		),
+		mcp.WithString("tool_name",
+			mcp.Description("Name of the tool, model, or entity to annotate (e.g. 'read_public_users', 'public.users')."),
+			mcp.Required(),
+		),
+		mcp.WithObject("annotations",
+			mcp.Description("Annotation data to store. Omit to retrieve existing annotations instead of setting them."),
+		),
+	)
+
+	h.mcpServer.AddTool(tool, func(ctx context.Context, req mcp.CallToolRequest) (*mcp.CallToolResult, error) {
+		args := req.GetArguments()
+
+		toolName, ok := args["tool_name"].(string)
+		if !ok || toolName == "" {
+			return mcp.NewToolResultError("missing required argument: tool_name"), nil
+		}
+
+		annotations, hasAnnotations := args["annotations"]
+
+		if hasAnnotations && annotations != nil {
+			return executeSetAnnotation(ctx, h, toolName, annotations)
+		}
+		return executeGetAnnotation(ctx, h, toolName)
+	})
+}
+
+func executeSetAnnotation(ctx context.Context, h *Handler, toolName string, annotations interface{}) (*mcp.CallToolResult, error) {
+	jsonBytes, err := json.Marshal(annotations)
+	if err != nil {
+		return mcp.NewToolResultError(fmt.Sprintf("failed to marshal annotations: %v", err)), nil
+	}
+
+	_, err = h.db.Exec(ctx, "SELECT resolvespec_set_annotation($1, $2)", toolName, string(jsonBytes))
+	if err != nil {
+		return mcp.NewToolResultError(fmt.Sprintf("failed to set annotation: %v", err)), nil
+	}
+
+	return marshalResult(map[string]interface{}{
+		"success":   true,
+		"tool_name": toolName,
+		"action":    "set",
+	})
+}
+
+func executeGetAnnotation(ctx context.Context, h *Handler, toolName string) (*mcp.CallToolResult, error) {
+	var rows []map[string]interface{}
+	err := h.db.Query(ctx, &rows, "SELECT resolvespec_get_annotation($1)", toolName)
+	if err != nil {
+		return mcp.NewToolResultError(fmt.Sprintf("failed to get annotation: %v", err)), nil
+	}
+
+	var annotations interface{}
+	if len(rows) > 0 {
+		// The procedure returns a single value; extract the first column of the first row.
+		for _, v := range rows[0] {
+			annotations = v
+			break
+		}
+	}
+
+	// If the value is a []byte or string containing JSON, decode it so it round-trips cleanly.
+	switch v := annotations.(type) {
+	case []byte:
+		var decoded interface{}
+		if json.Unmarshal(v, &decoded) == nil {
+			annotations = decoded
+		}
+	case string:
+		var decoded interface{}
+		if json.Unmarshal([]byte(v), &decoded) == nil {
+			annotations = decoded
+		}
+	}
+
+	return marshalResult(map[string]interface{}{
+		"success":     true,
+		"tool_name":   toolName,
+		"action":      "get",
+		"annotations": annotations,
+	})
+}

pkg/resolvemcp/handler.go

@@ -14,6 +14,7 @@ import (
 
 	"github.com/bitechdev/ResolveSpec/pkg/common"
 	"github.com/bitechdev/ResolveSpec/pkg/logger"
+	"github.com/bitechdev/ResolveSpec/pkg/modelregistry"
 	"github.com/bitechdev/ResolveSpec/pkg/reflection"
 )
 
@@ -30,7 +31,7 @@ type Handler struct {
 
 // NewHandler creates a Handler with the given database, model registry, and config.
 func NewHandler(db common.Database, registry common.ModelRegistry, cfg Config) *Handler {
-	return &Handler{
+	h := &Handler{
 		db:        db,
 		registry:  registry,
 		hooks:     NewHookRegistry(),
@@ -39,6 +40,8 @@ func NewHandler(db common.Database, registry common.ModelRegistry, cfg Config) *
 		name:      "resolvemcp",
 		version:   "1.0.0",
 	}
+	registerAnnotationTool(h)
+	return h
 }
 
 // Hooks returns the hook registry.
@@ -66,6 +69,14 @@ func (h *Handler) SSEServer() http.Handler {
 	return &dynamicSSEHandler{h: h}
 }
 
+// StreamableHTTPServer returns an http.Handler that serves MCP over the streamable HTTP transport.
+// Unlike SSE (which requires two endpoints), streamable HTTP uses a single endpoint for all
+// client-server communication (POST for requests, GET for server-initiated messages).
+// Mount the returned handler at the desired path; the path itself becomes the MCP endpoint.
+func (h *Handler) StreamableHTTPServer() http.Handler {
+	return server.NewStreamableHTTPServer(h.mcpServer)
+}
+
 // newSSEServer creates a concrete *server.SSEServer for known baseURL and basePath values.
 func (h *Handler) newSSEServer(baseURL, basePath string) *server.SSEServer {
 	return server.NewSSEServer(
@@ -123,6 +134,32 @@ func (h *Handler) RegisterModel(schema, entity string, model interface{}) error
 	return nil
 }
 
+// RegisterModelWithRules registers a model and sets per-entity operation rules
+// (CanRead, CanCreate, CanUpdate, CanDelete, CanPublic*, SecurityDisabled).
+// Requires RegisterSecurityHooks to have been called for the rules to be enforced.
+func (h *Handler) RegisterModelWithRules(schema, entity string, model interface{}, rules modelregistry.ModelRules) error {
+	reg, ok := h.registry.(*modelregistry.DefaultModelRegistry)
+	if !ok {
+		return fmt.Errorf("resolvemcp: registry does not support model rules (use NewHandlerWithGORM/Bun/DB)")
+	}
+	fullName := buildModelName(schema, entity)
+	if err := reg.RegisterModelWithRules(fullName, model, rules); err != nil {
+		return err
+	}
+	registerModelTools(h, schema, entity, model)
+	return nil
+}
+
+// SetModelRules updates the operation rules for an already-registered model.
+// Requires RegisterSecurityHooks to have been called for the rules to be enforced.
+func (h *Handler) SetModelRules(schema, entity string, rules modelregistry.ModelRules) error {
+	reg, ok := h.registry.(*modelregistry.DefaultModelRegistry)
+	if !ok {
+		return fmt.Errorf("resolvemcp: registry does not support model rules (use NewHandlerWithGORM/Bun/DB)")
+	}
+	return reg.SetModelRules(buildModelName(schema, entity), rules)
+}
+
 // buildModelName builds the registry key for a model (same format as resolvespec).
 func buildModelName(schema, entity string) string {
 	if schema == "" {

pkg/resolvemcp/resolvemcp.go

@@ -98,3 +98,36 @@ func SetupBunRouterRoutes(router *bunrouter.Router, handler *Handler) {
 func NewSSEServer(handler *Handler) http.Handler {
 	return handler.SSEServer()
 }
+
+// SetupMuxStreamableHTTPRoutes mounts the MCP streamable HTTP endpoint on the given Gorilla Mux router.
+// The streamable HTTP transport uses a single endpoint (Config.BasePath) for all communication:
+// POST for client→server messages, GET for server→client streaming.
+//
+// Example:
+//
+//	resolvemcp.SetupMuxStreamableHTTPRoutes(r, handler) // mounts at Config.BasePath
+func SetupMuxStreamableHTTPRoutes(muxRouter *mux.Router, handler *Handler) {
+	basePath := handler.config.BasePath
+	h := handler.StreamableHTTPServer()
+	muxRouter.PathPrefix(basePath).Handler(http.StripPrefix(basePath, h))
+}
+
+// SetupBunRouterStreamableHTTPRoutes mounts the MCP streamable HTTP endpoint on a bunrouter router.
+// The streamable HTTP transport uses a single endpoint (Config.BasePath).
+func SetupBunRouterStreamableHTTPRoutes(router *bunrouter.Router, handler *Handler) {
+	basePath := handler.config.BasePath
+	h := handler.StreamableHTTPServer()
+	router.GET(basePath, bunrouter.HTTPHandler(h))
+	router.POST(basePath, bunrouter.HTTPHandler(h))
+	router.DELETE(basePath, bunrouter.HTTPHandler(h))
+}
+
+// NewStreamableHTTPHandler returns an http.Handler that serves MCP over the streamable HTTP transport.
+// Mount it at the desired path; that path becomes the MCP endpoint.
+//
+//	h := resolvemcp.NewStreamableHTTPHandler(handler)
+//	http.Handle("/mcp", h)
+//	engine.Any("/mcp", gin.WrapH(h))
+func NewStreamableHTTPHandler(handler *Handler) http.Handler {
+	return handler.StreamableHTTPServer()
+}

pkg/resolvemcp/security_hooks.go

@@ -0,0 +1,115 @@
+package resolvemcp
+
+import (
+	"context"
+	"net/http"
+
+	"github.com/bitechdev/ResolveSpec/pkg/common"
+	"github.com/bitechdev/ResolveSpec/pkg/logger"
+	"github.com/bitechdev/ResolveSpec/pkg/security"
+)
+
+// RegisterSecurityHooks wires the security package's access-control layer into the
+// resolvemcp handler. Call it once after creating the handler, before registering models.
+//
+// The following controls are applied:
+//   - Per-entity operation rules (CanRead, CanCreate, CanUpdate, CanDelete, CanPublic*)
+//     stored via RegisterModelWithRules / SetModelRules.
+//   - Row-level security: WHERE clause injected per user from the SecurityList provider.
+//   - Column-level security: sensitive columns masked/hidden in read results.
+//   - Audit logging after each read.
+func RegisterSecurityHooks(handler *Handler, securityList *security.SecurityList) {
+	// BeforeHandle: enforce model-level operation rules (auth check).
+	handler.Hooks().Register(BeforeHandle, func(hookCtx *HookContext) error {
+		if err := security.CheckModelAuthAllowed(newSecurityContext(hookCtx), hookCtx.Operation); err != nil {
+			hookCtx.Abort = true
+			hookCtx.AbortMessage = err.Error()
+			hookCtx.AbortCode = http.StatusUnauthorized
+			return err
+		}
+		return nil
+	})
+
+	// BeforeRead (1st): load RLS + CLS rules from the provider into SecurityList.
+	handler.Hooks().Register(BeforeRead, func(hookCtx *HookContext) error {
+		return security.LoadSecurityRules(newSecurityContext(hookCtx), securityList)
+	})
+
+	// BeforeRead (2nd): apply row-level security — injects a WHERE clause into the query.
+	// resolvemcp has no separate BeforeScan hook; the query is available in BeforeRead.
+	handler.Hooks().Register(BeforeRead, func(hookCtx *HookContext) error {
+		return security.ApplyRowSecurity(newSecurityContext(hookCtx), securityList)
+	})
+
+	// AfterRead (1st): apply column-level security — mask/hide columns in the result.
+	handler.Hooks().Register(AfterRead, func(hookCtx *HookContext) error {
+		return security.ApplyColumnSecurity(newSecurityContext(hookCtx), securityList)
+	})
+
+	// AfterRead (2nd): audit log.
+	handler.Hooks().Register(AfterRead, func(hookCtx *HookContext) error {
+		return security.LogDataAccess(newSecurityContext(hookCtx))
+	})
+
+	// BeforeUpdate: enforce CanUpdate rule.
+	handler.Hooks().Register(BeforeUpdate, func(hookCtx *HookContext) error {
+		return security.CheckModelUpdateAllowed(newSecurityContext(hookCtx))
+	})
+
+	// BeforeDelete: enforce CanDelete rule.
+	handler.Hooks().Register(BeforeDelete, func(hookCtx *HookContext) error {
+		return security.CheckModelDeleteAllowed(newSecurityContext(hookCtx))
+	})
+
+	logger.Info("Security hooks registered for resolvemcp handler")
+}
+
+// --------------------------------------------------------------------------
+// securityContext — adapts resolvemcp.HookContext to security.SecurityContext
+// --------------------------------------------------------------------------
+
+type securityContext struct {
+	ctx *HookContext
+}
+
+func newSecurityContext(ctx *HookContext) security.SecurityContext {
+	return &securityContext{ctx: ctx}
+}
+
+func (s *securityContext) GetContext() context.Context {
+	return s.ctx.Context
+}
+
+func (s *securityContext) GetUserID() (int, bool) {
+	return security.GetUserID(s.ctx.Context)
+}
+
+func (s *securityContext) GetSchema() string {
+	return s.ctx.Schema
+}
+
+func (s *securityContext) GetEntity() string {
+	return s.ctx.Entity
+}
+
+func (s *securityContext) GetModel() interface{} {
+	return s.ctx.Model
+}
+
+func (s *securityContext) GetQuery() interface{} {
+	return s.ctx.Query
+}
+
+func (s *securityContext) SetQuery(query interface{}) {
+	if q, ok := query.(common.SelectQuery); ok {
+		s.ctx.Query = q
+	}
+}
+
+func (s *securityContext) GetResult() interface{} {
+	return s.ctx.Result
+}
+
+func (s *securityContext) SetResult(result interface{}) {
+	s.ctx.Result = result
+}