chore(release): update package version to 1.0.63

Reviewed-on: #8

cmd/relspec/assets.go

@@ -0,0 +1,214 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/spf13/cobra"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/assetloader"
+	"git.warky.dev/wdevs/relspecgo/pkg/pgsql"
+)
+
+var (
+	assetsDir          string
+	assetsConn         string
+	assetsIgnoreErrors bool
+)
+
+var assetsCmd = &cobra.Command{
+	Use:   "assets",
+	Short: "Load and execute asset manifests against a database",
+	Long: `Load local binary and text asset files into a PostgreSQL database.
+
+Assets are described by YAML manifests (assets.yaml) colocated with the files.
+Each manifest entry specifies the file to load and the SQL call to execute.
+File bytes are bound as native pgx parameters — never as SQL text literals —
+so binary files stay byte-exact with no size or encoding limitations.
+
+Manifests must live in directories that follow the naming pattern used by
+relspec scripts:
+  {priority}_{sequence}_{name}/   or   {priority}-{sequence}-{name}/
+
+This allows asset-loading steps to be ordered correctly alongside SQL scripts
+in a migrate-apply pipeline.
+
+Manifest format (assets.yaml):
+  - file: invoice.md
+    call: |
+      INSERT INTO org.filepointer (rid_owner, filename, contenttype, jsonstore)
+      VALUES (1, :filename, 'text/markdown', jsonb_build_object('content', :bytes::text))
+  - file: logo.png
+    call: UPDATE branding SET logo = :bytes WHERE id = 1
+    params:
+      owner_id: "42"
+
+Built-in placeholders:
+  :bytes    — the file's raw content as bytea
+  :filename — the base name of the file (string)
+  :any_key  — a static value declared in the entry's params map`,
+}
+
+var assetsListCmd = &cobra.Command{
+	Use:   "list",
+	Short: "List asset manifests from a directory",
+	Long: `List all asset manifest entries from a directory in execution order.
+
+The directory is scanned recursively for assets.yaml files located in
+directories that follow the {priority}_{sequence}_{name} naming convention.
+
+Example:
+  relspec assets list --dir ./sql`,
+	RunE: runAssetsList,
+}
+
+var assetsExecuteCmd = &cobra.Command{
+	Use:   "execute",
+	Short: "Execute asset manifests against a database",
+	Long: `Execute asset manifest entries from a directory against a PostgreSQL database.
+
+Asset manifests are executed in order: Priority (ascending), Sequence (ascending),
+Directory name (alphabetical). By default, execution stops on the first error.
+Use --ignore-errors to continue even when individual entries fail.
+
+PostgreSQL Connection String Examples:
+  postgres://username:password@localhost:5432/database_name
+  postgresql://user:pass@host/dbname?sslmode=disable
+
+Examples:
+  relspec assets execute --dir ./sql \
+                         --conn "postgres://user:pass@localhost:5432/mydb"
+
+  relspec assets execute --dir ./sql \
+                         --conn "postgres://localhost/mydb" \
+                         --ignore-errors`,
+	RunE: runAssetsExecute,
+}
+
+func init() {
+	assetsListCmd.Flags().StringVar(&assetsDir, "dir", "", "Directory to scan for asset manifests (required)")
+	if err := assetsListCmd.MarkFlagRequired("dir"); err != nil {
+		fmt.Fprintf(os.Stderr, "Error marking dir flag as required: %v\n", err)
+	}
+
+	assetsExecuteCmd.Flags().StringVar(&assetsDir, "dir", "", "Directory to scan for asset manifests (required)")
+	assetsExecuteCmd.Flags().StringVar(&assetsConn, "conn", "", "PostgreSQL connection string (required)")
+	assetsExecuteCmd.Flags().BoolVar(&assetsIgnoreErrors, "ignore-errors", false, "Continue executing even if entries fail")
+	if err := assetsExecuteCmd.MarkFlagRequired("dir"); err != nil {
+		fmt.Fprintf(os.Stderr, "Error marking dir flag as required: %v\n", err)
+	}
+	if err := assetsExecuteCmd.MarkFlagRequired("conn"); err != nil {
+		fmt.Fprintf(os.Stderr, "Error marking conn flag as required: %v\n", err)
+	}
+
+	assetsCmd.AddCommand(assetsListCmd)
+	assetsCmd.AddCommand(assetsExecuteCmd)
+}
+
+func runAssetsList(cmd *cobra.Command, args []string) error {
+	fmt.Fprintf(os.Stderr, "\n=== Asset Manifests List ===\n")
+	fmt.Fprintf(os.Stderr, "Directory: %s\n\n", assetsDir)
+
+	items, err := assetloader.ScanDir(assetsDir)
+	if err != nil {
+		return fmt.Errorf("scanning directory: %w", err)
+	}
+
+	if len(items) == 0 {
+		fmt.Fprintf(os.Stderr, "No asset manifests found.\n\n")
+		return nil
+	}
+
+	fmt.Fprintf(os.Stderr, "Found %d asset entry(ies) in execution order:\n\n", len(items))
+	fmt.Fprintf(os.Stderr, "%-4s %-10s %-8s %-20s %s\n", "No.", "Priority", "Sequence", "Dir", "File")
+	fmt.Fprintf(os.Stderr, "%-4s %-10s %-8s %-20s %s\n", "----", "--------", "--------", "--------------------", "----")
+
+	for i, item := range items {
+		fmt.Fprintf(os.Stderr, "%-4d %-10d %-8d %-20s %s\n",
+			i+1,
+			item.Priority,
+			item.Sequence,
+			item.DirName,
+			filepath.Base(item.Entry.File),
+		)
+	}
+
+	fmt.Fprintf(os.Stderr, "\n")
+	return nil
+}
+
+func runAssetsExecute(cmd *cobra.Command, args []string) error {
+	fmt.Fprintf(os.Stderr, "\n=== Asset Manifests Execution ===\n")
+	fmt.Fprintf(os.Stderr, "Started at: %s\n", getCurrentTimestamp())
+	fmt.Fprintf(os.Stderr, "Directory: %s\n", assetsDir)
+	fmt.Fprintf(os.Stderr, "Database:  %s\n\n", maskPassword(assetsConn))
+
+	fmt.Fprintf(os.Stderr, "[1/2] Scanning asset manifests...\n")
+
+	items, err := assetloader.ScanDir(assetsDir)
+	if err != nil {
+		return fmt.Errorf("scanning directory: %w", err)
+	}
+
+	if len(items) == 0 {
+		fmt.Fprintf(os.Stderr, "      No asset manifests found. Nothing to execute.\n\n")
+		return nil
+	}
+
+	fmt.Fprintf(os.Stderr, "      ✓ Found %d asset entry(ies)\n\n", len(items))
+
+	fmt.Fprintf(os.Stderr, "[2/2] Executing assets in order (Priority → Sequence → Dir)...\n\n")
+
+	ctx := context.Background()
+	conn, err := pgsql.Connect(ctx, assetsConn, "assets-execute")
+	if err != nil {
+		return fmt.Errorf("connecting to database: %w", err)
+	}
+	defer conn.Close(ctx)
+
+	successCount := 0
+	var failures []struct {
+		item assetloader.Item
+		err  error
+	}
+
+	for _, item := range items {
+		name := filepath.Base(item.Entry.File)
+		fmt.Printf("Executing asset: %s (Priority=%d, Sequence=%d, Dir=%s)\n",
+			name, item.Priority, item.Sequence, item.DirName)
+
+		if err := assetloader.ExecuteItem(ctx, conn, item); err != nil {
+			if assetsIgnoreErrors {
+				fmt.Printf("⚠ Error loading %s: %v (continuing due to --ignore-errors)\n", name, err)
+				failures = append(failures, struct {
+					item assetloader.Item
+					err  error
+				}{item, err})
+				continue
+			}
+			return fmt.Errorf("asset %s (Priority=%d, Sequence=%d): %w",
+				name, item.Priority, item.Sequence, err)
+		}
+
+		successCount++
+		fmt.Printf("✓ Successfully loaded: %s\n", name)
+	}
+
+	fmt.Fprintf(os.Stderr, "\n=== Execution Complete ===\n")
+	fmt.Fprintf(os.Stderr, "Completed at: %s\n", getCurrentTimestamp())
+	fmt.Fprintf(os.Stderr, "Total entries: %d\n", len(items))
+	fmt.Fprintf(os.Stderr, "Successful:    %d\n", successCount)
+	if len(failures) > 0 {
+		fmt.Fprintf(os.Stderr, "Failed:        %d\n", len(failures))
+		fmt.Fprintf(os.Stderr, "\n⚠ Failed Entries Summary (%d failed):\n", len(failures))
+		for i, f := range failures {
+			fmt.Fprintf(os.Stderr, "  %d. %s (Priority=%d, Sequence=%d)\n     Error: %v\n",
+				i+1, filepath.Base(f.item.Entry.File), f.item.Priority, f.item.Sequence, f.err)
+		}
+	}
+	fmt.Fprintf(os.Stderr, "\n")
+
+	return nil
+}

cmd/relspec/convert.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	stdjson "encoding/json"
 	"fmt"
 	"os"
 	"strings"
@@ -54,6 +55,7 @@ var (
 	convertFlattenSchema   bool
 	convertNullableTypes   string
 	convertContinueOnError bool
+	convertExtraFields     string
 )
 
 var convertCmd = &cobra.Command{
@@ -179,6 +181,7 @@ func init() {
 	convertCmd.Flags().BoolVar(&convertFlattenSchema, "flatten-schema", false, "Flatten schema.table names to schema_table (useful for databases like SQLite that do not support schemas)")
 	convertCmd.Flags().StringVar(&convertNullableTypes, "types", "", "Nullable type package for code-gen writers (bun/gorm): 'baselib' (default, Go pointer types), 'stdlib' (database/sql), or 'sqltypes'")
 	convertCmd.Flags().BoolVar(&convertContinueOnError, "continue-on-error", false, "Prepend \\set ON_ERROR_STOP off to generated SQL so psql continues past errors (pgsql output only)")
+	convertCmd.Flags().StringVar(&convertExtraFields, "extra-fields", "", "Path to JSON file containing extra Bun model fields to inject (bun output only); fields support target_table, name, type, bun_tag, json_tag, comment")
 
 	err := convertCmd.MarkFlagRequired("from")
 	if err != nil {
@@ -245,7 +248,7 @@ func runConvert(cmd *cobra.Command, args []string) error {
 		fmt.Fprintf(os.Stderr, "      Schema: %s\n", convertSchemaFilter)
 	}
 
-	if err := writeDatabase(db, convertTargetType, convertTargetPath, convertPackageName, convertSchemaFilter, convertFlattenSchema, convertNullableTypes, convertContinueOnError); err != nil {
+	if err := writeDatabase(db, convertTargetType, convertTargetPath, convertPackageName, convertSchemaFilter, convertFlattenSchema, convertNullableTypes, convertContinueOnError, convertExtraFields); err != nil {
 		return fmt.Errorf("failed to write target: %w", err)
 	}
 
@@ -385,10 +388,30 @@ func readDatabaseForConvert(dbType, filePath, connString string) (*models.Databa
 	return db, nil
 }
 
-func writeDatabase(db *models.Database, dbType, outputPath, packageName, schemaFilter string, flattenSchema bool, nullableTypes string, continueOnError bool) error {
+func writeDatabase(db *models.Database, dbType, outputPath, packageName, schemaFilter string, flattenSchema bool, nullableTypes string, continueOnError bool, extraFields string) error {
 	var writer writers.Writer
 
 	writerOpts := newWriterOptions(outputPath, packageName, flattenSchema, nullableTypes, continueOnError)
+	if extraFields != "" {
+		if !strings.EqualFold(dbType, "bun") {
+			return fmt.Errorf("--extra-fields is only supported for Bun output")
+		}
+		extraFieldsJSON, err := os.ReadFile(extraFields)
+		if err != nil {
+			return fmt.Errorf("failed to read --extra-fields file %q: %w", extraFields, err)
+		}
+
+		var parsed []wbun.ExtraFieldConfig
+		if err := stdjson.Unmarshal(extraFieldsJSON, &parsed); err != nil {
+			return fmt.Errorf("invalid --extra-fields JSON in %q: %w", extraFields, err)
+		}
+		if len(parsed) == 0 {
+			return fmt.Errorf("--extra-fields must contain at least one field")
+		}
+		writerOpts.Metadata = map[string]interface{}{
+			"extra_fields": string(extraFieldsJSON),
+		}
+	}
 
 	switch strings.ToLower(dbType) {
 	case "dbml":

cmd/relspec/root.go

@@ -64,6 +64,7 @@ func init() {
 	rootCmd.AddCommand(diffCmd)
 	rootCmd.AddCommand(inspectCmd)
 	rootCmd.AddCommand(scriptsCmd)
+	rootCmd.AddCommand(assetsCmd)
 	rootCmd.AddCommand(templCmd)
 	rootCmd.AddCommand(editCmd)
 	rootCmd.AddCommand(mergeCmd)

cmd/relspec/split.go

@@ -189,6 +189,7 @@ func runSplit(cmd *cobra.Command, args []string) error {
 		false, // no flatten-schema for split
 		splitNullableTypes,
 		false, // no continue-on-error for split
+		"",    // no extra fields for split
 	)
 	if err != nil {
 		return fmt.Errorf("failed to write output: %w", err)

linux/arch/PKGBUILD

@@ -1,6 +1,6 @@
 # Maintainer: Hein (Warky Devs) <hein@warky.dev>
 pkgname=relspec
-pkgver=1.0.62
+pkgver=1.0.63
 pkgrel=1
 pkgdesc="RelSpec is a comprehensive database relations management tool that reads, transforms, and writes database table specifications across multiple formats and ORMs."
 arch=('x86_64' 'aarch64')

linux/centos/relspec.spec

@@ -1,5 +1,5 @@
 Name:           relspec
-Version:        1.0.62
+Version:        1.0.63
 Release:        1%{?dist}
 Summary:        RelSpec is a comprehensive database relations management tool that reads, transforms, and writes database table specifications across multiple formats and ORMs.
 

pkg/assetloader/executor.go

@@ -0,0 +1,106 @@
+package assetloader
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+
+	"github.com/jackc/pgx/v5"
+)
+
+// namedPlaceholder matches :identifier patterns (but not ::cast syntax).
+var namedPlaceholder = regexp.MustCompile(`:([a-zA-Z_][a-zA-Z0-9_]*)`)
+
+// pgCastMarker temporarily replaces :: to protect PostgreSQL cast syntax.
+const pgCastMarker = "\x00PGCAST\x00"
+
+// BuildQuery converts a SQL call that uses :name named placeholders into a
+// pgx-compatible positional-parameter query ($1, $2, …) and returns the
+// corresponding argument slice.
+//
+// Built-in placeholders:
+//   - :bytes    → fileBytes ([]byte)
+//   - :filename → filename (string, base name only)
+//   - :any_key  → staticParams["any_key"] (string)
+//
+// A placeholder that appears more than once maps to the same $N. An unknown
+// placeholder (not built-in and not in staticParams) returns an error.
+// PostgreSQL cast syntax (::type) is left untouched.
+func BuildQuery(call string, fileBytes []byte, filename string, staticParams map[string]string) (query string, args []any, err error) {
+	// Protect :: casts before running the placeholder regex.
+	protected := strings.ReplaceAll(call, "::", pgCastMarker)
+
+	paramIndex := map[string]int{} // name → 1-based position
+	var firstErr error
+
+	query = namedPlaceholder.ReplaceAllStringFunc(protected, func(match string) string {
+		if firstErr != nil {
+			return match
+		}
+		name := match[1:] // strip leading ':'
+
+		// Return existing positional param for repeated placeholders.
+		if idx, seen := paramIndex[name]; seen {
+			return fmt.Sprintf("$%d", idx)
+		}
+
+		// Resolve the placeholder value.
+		var val any
+		switch name {
+		case "bytes":
+			val = fileBytes
+		case "filename":
+			val = filename
+		default:
+			if staticParams != nil {
+				if v, ok := staticParams[name]; ok {
+					val = v
+				}
+			}
+			if val == nil {
+				firstErr = fmt.Errorf("unknown placeholder %q in SQL call (not a built-in and not listed in params)", match)
+				return match
+			}
+		}
+
+		idx := len(args) + 1
+		paramIndex[name] = idx
+		args = append(args, val)
+		return fmt.Sprintf("$%d", idx)
+	})
+
+	if firstErr != nil {
+		return "", nil, firstErr
+	}
+
+	// Restore :: casts.
+	query = strings.ReplaceAll(query, pgCastMarker, "::")
+
+	return query, args, nil
+}
+
+// ExecuteItem reads the asset file referenced by item.Entry.File (which is the
+// absolute path set by ScanDir) and executes the configured SQL call via conn.
+// The file's raw bytes are bound as a []byte parameter — no encoding or escaping.
+func ExecuteItem(ctx context.Context, conn *pgx.Conn, item Item) error {
+	data, err := os.ReadFile(item.Entry.File)
+	if err != nil {
+		return fmt.Errorf("reading asset file %s: %w", item.Entry.File, err)
+	}
+
+	filename := filepath.Base(item.Entry.File)
+
+	sql, args, err := BuildQuery(item.Entry.Call, data, filename, item.Entry.Params)
+	if err != nil {
+		return fmt.Errorf("building query for %s: %w", filename, err)
+	}
+
+	if _, err := conn.Exec(ctx, sql, args...); err != nil {
+		return fmt.Errorf("executing asset %s: %w", filename, err)
+	}
+
+	return nil
+}

pkg/assetloader/loader.go

@@ -0,0 +1,200 @@
+// Package assetloader implements a native Go asset/file loader that binds
+// local binary and text files as pgx query parameters during database seeding.
+// Files are bound as actual []byte query parameters — never converted to SQL
+// text literals — so binary data stays byte-exact and no escaping is needed.
+//
+// Manifests are small YAML files (assets.yaml) that describe, per file, the
+// SQL call to invoke and the named placeholders for :bytes, :filename, and any
+// static column values. Manifests live inside directories that follow the same
+// {priority}_{sequence}_{name} naming convention used by the sqldir reader,
+// so asset-loading steps can be interleaved with SQL scripts in a migrate-apply
+// run.
+package assetloader
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"regexp"
+	"sort"
+	"strconv"
+	"strings"
+
+	"gopkg.in/yaml.v3"
+)
+
+// ManifestEntry describes a single file to load from an assets.yaml manifest.
+type ManifestEntry struct {
+	// File is the path to the asset file, relative to the manifest directory.
+	File string `yaml:"file"`
+	// Call is the SQL statement to execute. Use :bytes for file content,
+	// :filename for the base name, and :param_name for static params.
+	Call string `yaml:"call"`
+	// Params holds optional static named parameters referenced in Call.
+	Params map[string]string `yaml:"params,omitempty"`
+}
+
+// Item combines a manifest entry with its ordering metadata and the resolved
+// directory where the manifest and asset file reside.
+type Item struct {
+	// Priority and Sequence come from the parent directory's naming pattern.
+	Priority int
+	Sequence uint
+	// DirName is the last path component of the manifest's directory.
+	DirName string
+	// Dir is the absolute path to the directory containing assets.yaml and files.
+	Dir string
+	// Entry is the parsed manifest entry.
+	Entry ManifestEntry
+}
+
+// dirPattern matches {priority}_{sequence}_{name} or {priority}-{sequence}-{name}
+// directory names, e.g. "1_010_seed_templates" or "2-001-branding".
+var dirPattern = regexp.MustCompile(`^(\d+)[_-](\d+)[_-](.+)$`)
+
+// LoadManifest reads and parses the assets.yaml file in dir, returning
+// the ordered list of manifest entries. Returns an error if assets.yaml is
+// absent or contains invalid YAML.
+func LoadManifest(dir string) ([]ManifestEntry, error) {
+	manifestPath := filepath.Join(dir, "assets.yaml")
+	data, err := os.ReadFile(manifestPath)
+	if err != nil {
+		return nil, fmt.Errorf("reading %s: %w", manifestPath, err)
+	}
+
+	var entries []ManifestEntry
+	if err := yaml.Unmarshal(data, &entries); err != nil {
+		return nil, fmt.Errorf("parsing %s: %w", manifestPath, err)
+	}
+
+	return entries, nil
+}
+
+// ScanDir recursively walks baseDir, finds all assets.yaml manifests, resolves
+// each file entry (skipping symlinks and path traversal), and returns the
+// resulting Items sorted by (Priority, Sequence, DirName).
+//
+// Each manifest must reside in a directory whose name follows the
+// {priority}_{sequence}_{name} pattern. Manifests in directories that do not
+// follow this convention are assigned Priority=0, Sequence=0 and sorted last.
+func ScanDir(baseDir string) ([]Item, error) {
+	absBase, err := filepath.Abs(baseDir)
+	if err != nil {
+		return nil, fmt.Errorf("resolving base dir: %w", err)
+	}
+
+	var items []Item
+
+	err = filepath.WalkDir(absBase, func(path string, d os.DirEntry, walkErr error) error {
+		if walkErr != nil {
+			return walkErr
+		}
+		if d.IsDir() {
+			return nil
+		}
+		if d.Name() != "assets.yaml" {
+			return nil
+		}
+
+		manifestDir := filepath.Dir(path)
+		priority, sequence, dirName := parseDirName(filepath.Base(manifestDir))
+
+		entries, err := LoadManifest(manifestDir)
+		if err != nil {
+			return fmt.Errorf("loading manifest in %s: %w", manifestDir, err)
+		}
+
+		for _, entry := range entries {
+			if entry.File == "" || entry.Call == "" {
+				continue
+			}
+
+			// Resolve and validate the asset file path.
+			resolved, skip, err := resolveAssetPath(absBase, manifestDir, entry.File)
+			if err != nil {
+				return err
+			}
+			if skip {
+				continue
+			}
+
+			items = append(items, Item{
+				Priority: priority,
+				Sequence: sequence,
+				DirName:  dirName,
+				Dir:      manifestDir,
+				Entry: ManifestEntry{
+					File:   resolved, // absolute path, safe to read
+					Call:   entry.Call,
+					Params: entry.Params,
+				},
+			})
+		}
+
+		return nil
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	sort.SliceStable(items, func(i, j int) bool {
+		if items[i].Priority != items[j].Priority {
+			return items[i].Priority < items[j].Priority
+		}
+		if items[i].Sequence != items[j].Sequence {
+			return items[i].Sequence < items[j].Sequence
+		}
+		return items[i].DirName < items[j].DirName
+	})
+
+	return items, nil
+}
+
+// parseDirName extracts (priority, sequence, name) from a directory name that
+// follows the {priority}[_-]{sequence}[_-]{name} convention. Returns (0, 0, dir)
+// when the name does not match.
+func parseDirName(dir string) (priority int, sequence uint, name string) {
+	m := dirPattern.FindStringSubmatch(dir)
+	if m == nil {
+		return 0, 0, dir
+	}
+	p, _ := strconv.Atoi(m[1])
+	s, _ := strconv.ParseUint(m[2], 10, 64)
+	return p, uint(s), m[3]
+}
+
+// resolveAssetPath resolves a manifest-relative file path and checks that:
+//   - it does not escape the base directory (path traversal prevention)
+//   - none of its path components are symlinks
+//
+// Returns the absolute path, a skip flag (true when the entry should be silently
+// dropped), and any hard error.
+func resolveAssetPath(absBase, manifestDir, file string) (absPath string, skip bool, err error) {
+	// Clean and join before any symlink resolution so we can detect traversal.
+	joined := filepath.Join(manifestDir, filepath.Clean(file))
+
+	// Ensure the cleaned path is still inside absBase.
+	rel, err := filepath.Rel(absBase, joined)
+	if err != nil || strings.HasPrefix(rel, "..") {
+		// Path escapes the base directory; skip silently.
+		return "", true, nil
+	}
+
+	// Walk each component to detect symlinks.
+	parts := strings.Split(rel, string(filepath.Separator))
+	current := absBase
+	for _, part := range parts {
+		current = filepath.Join(current, part)
+		info, statErr := os.Lstat(current)
+		if statErr != nil {
+			// File doesn't exist; skip.
+			return "", true, nil
+		}
+		if info.Mode()&os.ModeSymlink != 0 {
+			// Symlink in path; skip silently.
+			return "", true, nil
+		}
+	}
+
+	return joined, false, nil
+}

pkg/assetloader/loader_test.go

@@ -0,0 +1,341 @@
+package assetloader_test
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/assetloader"
+)
+
+func TestLoadManifest_ValidList(t *testing.T) {
+	dir := t.TempDir()
+	writeFile(t, dir, "assets.yaml", `
+- file: hello.txt
+  call: INSERT INTO files (name, data) VALUES (:filename, :bytes)
+- file: logo.png
+  call: UPDATE branding SET logo = :bytes WHERE id = 1
+`)
+	writeFile(t, dir, "hello.txt", "hello world")
+	writeFile(t, dir, "logo.png", "\x89PNG\r\n\x1a\n")
+
+	m, err := assetloader.LoadManifest(dir)
+	if err != nil {
+		t.Fatalf("LoadManifest failed: %v", err)
+	}
+	if len(m) != 2 {
+		t.Fatalf("expected 2 entries, got %d", len(m))
+	}
+	if m[0].File != "hello.txt" {
+		t.Errorf("entry 0 file: got %q, want %q", m[0].File, "hello.txt")
+	}
+	if m[1].File != "logo.png" {
+		t.Errorf("entry 1 file: got %q, want %q", m[1].File, "logo.png")
+	}
+}
+
+func TestLoadManifest_WithStaticParams(t *testing.T) {
+	dir := t.TempDir()
+	writeFile(t, dir, "assets.yaml", `
+- file: template.md
+  call: INSERT INTO templates (owner_id, name, data) VALUES (:owner_id, :filename, :bytes)
+  params:
+    owner_id: "42"
+`)
+	writeFile(t, dir, "template.md", "# Template")
+
+	m, err := assetloader.LoadManifest(dir)
+	if err != nil {
+		t.Fatalf("LoadManifest failed: %v", err)
+	}
+	if len(m) != 1 {
+		t.Fatalf("expected 1 entry, got %d", len(m))
+	}
+	if m[0].Params["owner_id"] != "42" {
+		t.Errorf("static param owner_id: got %q, want %q", m[0].Params["owner_id"], "42")
+	}
+}
+
+func TestLoadManifest_MissingFile(t *testing.T) {
+	dir := t.TempDir()
+	// No assets.yaml present
+	_, err := assetloader.LoadManifest(dir)
+	if err == nil {
+		t.Fatal("expected error for missing assets.yaml, got nil")
+	}
+}
+
+func TestLoadManifest_InvalidYAML(t *testing.T) {
+	dir := t.TempDir()
+	writeFile(t, dir, "assets.yaml", `{not: [valid yaml`)
+	_, err := assetloader.LoadManifest(dir)
+	if err == nil {
+		t.Fatal("expected error for invalid YAML, got nil")
+	}
+}
+
+func TestScanDir_FindsManifests(t *testing.T) {
+	root := t.TempDir()
+
+	// Directory named with priority-sequence pattern
+	dir1 := filepath.Join(root, "1_010_seed_templates")
+	if err := os.MkdirAll(dir1, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	writeFile(t, dir1, "assets.yaml", `
+- file: a.txt
+  call: INSERT INTO t (data) VALUES (:bytes)
+`)
+	writeFile(t, dir1, "a.txt", "aaa")
+
+	dir2 := filepath.Join(root, "2_001_branding")
+	if err := os.MkdirAll(dir2, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	writeFile(t, dir2, "assets.yaml", `
+- file: logo.png
+  call: UPDATE branding SET logo = :bytes
+`)
+	writeFile(t, dir2, "logo.png", "PNG")
+
+	items, err := assetloader.ScanDir(root)
+	if err != nil {
+		t.Fatalf("ScanDir failed: %v", err)
+	}
+	if len(items) != 2 {
+		t.Fatalf("expected 2 items, got %d", len(items))
+	}
+	// Should be ordered by priority then sequence
+	if items[0].Priority != 1 || items[0].Sequence != 10 {
+		t.Errorf("item[0]: got priority=%d seq=%d, want 1,10", items[0].Priority, items[0].Sequence)
+	}
+	if items[1].Priority != 2 || items[1].Sequence != 1 {
+		t.Errorf("item[1]: got priority=%d seq=%d, want 2,1", items[1].Priority, items[1].Sequence)
+	}
+}
+
+func TestScanDir_OrdersByPriorityThenSequence(t *testing.T) {
+	root := t.TempDir()
+
+	for _, d := range []string{"2_002_b", "1_001_a", "2_001_c", "1_002_d"} {
+		dir := filepath.Join(root, d)
+		if err := os.MkdirAll(dir, 0o755); err != nil {
+			t.Fatal(err)
+		}
+		writeFile(t, dir, "assets.yaml", `
+- file: x.txt
+  call: SELECT :bytes
+`)
+		writeFile(t, dir, "x.txt", "x")
+	}
+
+	items, err := assetloader.ScanDir(root)
+	if err != nil {
+		t.Fatalf("ScanDir failed: %v", err)
+	}
+	if len(items) != 4 {
+		t.Fatalf("expected 4 items, got %d", len(items))
+	}
+
+	type ps struct{ p int; s uint }
+	want := []ps{{1, 1}, {1, 2}, {2, 1}, {2, 2}}
+	for i, w := range want {
+		got := ps{items[i].Priority, items[i].Sequence}
+		if got != w {
+			t.Errorf("items[%d]: got {%d,%d}, want {%d,%d}", i, got.p, got.s, w.p, w.s)
+		}
+	}
+}
+
+func TestScanDir_SkipsSymlinks(t *testing.T) {
+	root := t.TempDir()
+
+	dir1 := filepath.Join(root, "1_001_real")
+	if err := os.MkdirAll(dir1, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	writeFile(t, dir1, "assets.yaml", `
+- file: a.txt
+  call: SELECT :bytes
+`)
+	writeFile(t, dir1, "a.txt", "real")
+
+	// Symlink to an asset file - should be skipped during file read
+	realFile := filepath.Join(root, "real.txt")
+	writeFile(t, root, "real.txt", "symlink target")
+	symlink := filepath.Join(dir1, "link.txt")
+	if err := os.Symlink(realFile, symlink); err != nil {
+		t.Skip("symlinks not supported:", err)
+	}
+
+	// Add a manifest entry that references the symlink
+	writeFile(t, dir1, "assets.yaml", `
+- file: a.txt
+  call: SELECT :bytes
+- file: link.txt
+  call: SELECT :bytes
+`)
+
+	items, err := assetloader.ScanDir(root)
+	if err != nil {
+		t.Fatalf("ScanDir failed: %v", err)
+	}
+	// The symlink entry should be skipped; only a.txt should remain
+	if len(items) != 1 {
+		t.Fatalf("expected 1 item after symlink skip, got %d", len(items))
+	}
+	if filepath.Base(items[0].Entry.File) != "a.txt" {
+		t.Errorf("expected non-symlink entry, got %q", items[0].Entry.File)
+	}
+}
+
+func TestScanDir_RejectsPathTraversal(t *testing.T) {
+	root := t.TempDir()
+
+	dir1 := filepath.Join(root, "1_001_evil")
+	if err := os.MkdirAll(dir1, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	writeFile(t, dir1, "assets.yaml", `
+- file: ../../etc/passwd
+  call: SELECT :bytes
+`)
+
+	items, err := assetloader.ScanDir(root)
+	if err != nil {
+		t.Fatalf("ScanDir failed: %v", err)
+	}
+	// Path traversal entry should be skipped
+	if len(items) != 0 {
+		t.Fatalf("expected 0 items after path traversal rejection, got %d", len(items))
+	}
+}
+
+func TestBuildQuery_BasicPlaceholders(t *testing.T) {
+	sql, args, err := assetloader.BuildQuery(
+		"INSERT INTO t (name, data) VALUES (:filename, :bytes)",
+		[]byte("hello"),
+		"hello.txt",
+		nil,
+	)
+	if err != nil {
+		t.Fatalf("BuildQuery failed: %v", err)
+	}
+	if sql != "INSERT INTO t (name, data) VALUES ($1, $2)" {
+		t.Errorf("unexpected SQL: %s", sql)
+	}
+	if len(args) != 2 {
+		t.Fatalf("expected 2 args, got %d", len(args))
+	}
+	if string(args[0].(string)) != "hello.txt" {
+		t.Errorf("args[0]: got %q, want %q", args[0], "hello.txt")
+	}
+	if string(args[1].([]byte)) != "hello" {
+		t.Errorf("args[1]: got %v, want %v", args[1], []byte("hello"))
+	}
+}
+
+func TestBuildQuery_StaticParams(t *testing.T) {
+	sql, args, err := assetloader.BuildQuery(
+		"INSERT INTO t (owner, name, data) VALUES (:owner_id, :filename, :bytes)",
+		[]byte("data"),
+		"file.bin",
+		map[string]string{"owner_id": "99"},
+	)
+	if err != nil {
+		t.Fatalf("BuildQuery failed: %v", err)
+	}
+	if sql != "INSERT INTO t (owner, name, data) VALUES ($1, $2, $3)" {
+		t.Errorf("unexpected SQL: %s", sql)
+	}
+	if len(args) != 3 {
+		t.Fatalf("expected 3 args, got %d: %v", len(args), args)
+	}
+	if args[0].(string) != "99" {
+		t.Errorf("args[0]: got %q, want %q", args[0], "99")
+	}
+}
+
+func TestBuildQuery_RepeatedPlaceholder(t *testing.T) {
+	sql, args, err := assetloader.BuildQuery(
+		"SELECT length(:bytes), encode(:bytes, 'base64')",
+		[]byte("abc"),
+		"f.bin",
+		nil,
+	)
+	if err != nil {
+		t.Fatalf("BuildQuery failed: %v", err)
+	}
+	// :bytes appears twice but maps to same $1
+	if sql != "SELECT length($1), encode($1, 'base64')" {
+		t.Errorf("unexpected SQL: %s", sql)
+	}
+	if len(args) != 1 {
+		t.Fatalf("expected 1 arg, got %d", len(args))
+	}
+}
+
+func TestBuildQuery_PostgresCastNotMatched(t *testing.T) {
+	// ::text should NOT be treated as a placeholder
+	sql, args, err := assetloader.BuildQuery(
+		"SELECT :bytes::text, :filename",
+		[]byte("data"),
+		"f.txt",
+		nil,
+	)
+	if err != nil {
+		t.Fatalf("BuildQuery failed: %v", err)
+	}
+	if sql != "SELECT $1::text, $2" {
+		t.Errorf("unexpected SQL: %s", sql)
+	}
+	if len(args) != 2 {
+		t.Fatalf("expected 2 args, got %d", len(args))
+	}
+}
+
+func TestBuildQuery_UnknownPlaceholder(t *testing.T) {
+	_, _, err := assetloader.BuildQuery(
+		"SELECT :unknown_param",
+		[]byte("data"),
+		"f.txt",
+		nil,
+	)
+	if err == nil {
+		t.Fatal("expected error for unknown placeholder, got nil")
+	}
+}
+
+func TestBuildQuery_BinaryFileByteExact(t *testing.T) {
+	// Binary data with null bytes, high bytes - must pass through unchanged
+	binary := []byte{0x00, 0xFF, 0x80, 0x01, 0xFE}
+	_, args, err := assetloader.BuildQuery(
+		"INSERT INTO blobs (data) VALUES (:bytes)",
+		binary,
+		"blob.bin",
+		nil,
+	)
+	if err != nil {
+		t.Fatalf("BuildQuery failed: %v", err)
+	}
+	if len(args) != 1 {
+		t.Fatalf("expected 1 arg")
+	}
+	got := args[0].([]byte)
+	if len(got) != len(binary) {
+		t.Fatalf("byte count: got %d, want %d", len(got), len(binary))
+	}
+	for i, b := range binary {
+		if got[i] != b {
+			t.Errorf("byte[%d]: got 0x%02x, want 0x%02x", i, got[i], b)
+		}
+	}
+}
+
+// writeFile is a test helper that writes content to a file.
+func writeFile(t *testing.T, dir, name, content string) {
+	t.Helper()
+	if err := os.WriteFile(filepath.Join(dir, name), []byte(content), 0o644); err != nil {
+		t.Fatalf("writeFile %s: %v", name, err)
+	}
+}

pkg/writers/bun/README.md

@@ -65,6 +65,12 @@ relspec convert --from pgsql --from-conn "postgres://localhost/mydb" \
 # Multi-file output (one file per table)
 relspec convert --from json --from-path schema.json \
   --to bun --to-path models/ --package models
+
+# Inject computed/scan-only fields that are not present in the database schema
+# (extra-fields.json contains the JSON array shown below)
+relspec convert --from dbml --from-path schema.dbml \
+  --to bun --to-path models.go --package models \
+  --extra-fields extra-fields.json
 ```
 
 ## Generated Code Examples
@@ -182,6 +188,61 @@ options := &writers.WriterOptions{
 }
 ```
 
+#### Extra fields
+
+Use `Metadata["extra_fields"]` (or the CLI `--extra-fields <path>` flag) to inject
+custom fields into generated Bun models without editing generated files. This is
+intended for computed columns and scan-only query fields that Bun must scan into
+but that are not real database table columns.
+
+The CLI flag expects a path to a JSON file, not inline JSON. This avoids shell
+quoting problems with struct tags and complex type names.
+
+Each entry supports:
+
+| Field | Required | Description |
+|---|---:|---|
+| `target_table` | No | Optional model scope. Accepts table name (`projects`), qualified table (`public.projects`), or model name (`ModelPublicProjects`). If omitted, the field is added to every generated model. |
+| `name` | Yes | Go struct field name. |
+| `type` | Yes | Go type to emit. |
+| `bun_tag` | No | Raw Bun tag contents, e.g. `thought_count,scanonly`. |
+| `json_tag` | No | Raw JSON tag contents. |
+| `comment` | No | Optional line comment. |
+
+```go
+options := &writers.WriterOptions{
+    OutputPath:  "models.go",
+    PackageName: "models",
+    Metadata: map[string]any{
+        "extra_fields": `[
+          {
+            "target_table": "projects",
+            "name": "ThoughtCount",
+            "type": "sql_types.SqlInt64",
+            "bun_tag": "thought_count,scanonly",
+            "json_tag": "thought_count",
+            "comment": "Computed by ResolveSpec queries"
+          }
+        ]`,
+    },
+}
+```
+
+Example `extra-fields.json`:
+
+```json
+[
+  {
+    "target_table": "projects",
+    "name": "ThoughtCount",
+    "type": "sql_types.SqlInt64",
+    "bun_tag": "thought_count,scanonly",
+    "json_tag": "thought_count",
+    "comment": "Computed by ResolveSpec queries"
+  }
+]
+```
+
 ## Notes
 
 - Model names are derived from table names (singularized, PascalCase)

pkg/writers/bun/template_data.go

@@ -1,6 +1,8 @@
 package bun
 
 import (
+	"encoding/json"
+	"fmt"
 	"sort"
 	"strings"
 
@@ -32,6 +34,90 @@ type ModelData struct {
 	PrimaryKeyIDType string // Helper method GetID/SetID/UpdateID type
 	IDColumnName     string // Name of the ID column in database
 	Prefix           string // 3-letter prefix
+
+	// ExtraFields are user-defined fields added via generator config (issue #4)
+	ExtraFields []*FieldData `json:"extra_fields,omitempty"`
+}
+
+// ExtraFieldConfig represents a custom field to be added to generated models
+type ExtraFieldConfig struct {
+	Name        string `json:"name"`
+	Type        string `json:"type"`
+	BunTag      string `json:"bun_tag,omitempty"`
+	JSONTag     string `json:"json_tag,omitempty"`
+	Comment     string `json:"comment,omitempty"`
+	TargetTable string `json:"target_table,omitempty"` // optional: if set, field only applies to this table
+}
+
+// LoadExtraFieldsFromMetadata loads custom field configurations from metadata map.
+// Accepts either a JSON-encoded array of fields (for CLI use) or a structured list
+// (for programmatic/sidecar file use). Each entry must have "name" and "type";
+// an optional "target_table" scopes the field to one table only.
+func LoadExtraFieldsFromMetadata(metadata map[string]interface{}) []ExtraFieldConfig {
+	if metadata == nil {
+		return nil
+	}
+
+	extraFieldsRaw, ok := metadata["extra_fields"]
+	if !ok || extraFieldsRaw == nil {
+		return nil
+	}
+
+	// Try to parse as JSON string first (from CLI flag)
+	if strVal, ok := extraFieldsRaw.(string); ok {
+		var fields []ExtraFieldConfig
+		if err := json.Unmarshal([]byte(strVal), &fields); err == nil && len(fields) > 0 {
+			return filterValidFields(fields)
+		}
+	}
+
+	// Try to parse as structured data (from sidecar file or programmatic API)
+	extraFieldsList, ok := extraFieldsRaw.([]interface{})
+	if !ok || len(extraFieldsList) == 0 {
+		return nil
+	}
+
+	fields := make([]ExtraFieldConfig, 0, len(extraFieldsList))
+	for _, item := range extraFieldsList {
+		if fieldMap, ok := item.(map[string]interface{}); ok {
+			field := ExtraFieldConfig{
+				Name:        toString(fieldMap["name"]),
+				Type:        toString(fieldMap["type"]),
+				BunTag:      toString(fieldMap["bun_tag"]),
+				JSONTag:     toString(fieldMap["json_tag"]),
+				Comment:     toString(fieldMap["comment"]),
+				TargetTable: toString(fieldMap["target_table"]),
+			}
+			if field.Name != "" && field.Type != "" {
+				fields = append(fields, field)
+			}
+		}
+	}
+
+	return filterValidFields(fields)
+}
+
+// filterValidFields removes entries that are missing required fields.
+func filterValidFields(fields []ExtraFieldConfig) []ExtraFieldConfig {
+	var valid []ExtraFieldConfig
+	for _, f := range fields {
+		if f.Name != "" && f.Type != "" {
+			valid = append(valid, f)
+		}
+	}
+	return valid
+}
+
+func toString(v interface{}) string {
+	if v == nil {
+		return ""
+	}
+	switch val := v.(type) {
+	case string:
+		return val
+	default:
+		return fmt.Sprintf("%v", val)
+	}
 }
 
 // FieldData represents a single field in a struct

pkg/writers/bun/templates.go

@@ -23,6 +23,13 @@ type {{.Name}} struct {
 {{- range .Fields}}
 	{{.Name}} {{.Type}} ` + "`bun:\"{{.BunTag}}\" json:\"{{.JSONTag}}\"`" + `{{if .Comment}} // {{.Comment}}{{end}}
 {{- end}}
+{{- if .ExtraFields}}
+
+	// --- Custom fields (managed by relspecgo generator config, issue #4) ---
+{{- range .ExtraFields}}
+	{{.Name}} {{.Type}} ` + "`bun:\"{{.BunTag}}\" json:\"{{.JSONTag}}\"`" + `{{if .Comment}} // {{.Comment}}{{end}}
+{{- end}}
+{{- end}}
 }
 {{if .Config.GenerateTableName}}
 // TableName returns the table name for {{.Name}}

pkg/writers/bun/writer.go

@@ -51,6 +51,43 @@ func (w *Writer) WriteDatabase(db *models.Database) error {
 	return w.writeSingleFile(db)
 }
 
+// addExtraFields appends user-defined extra fields to matching models.
+// Fields may be scoped by target_table (table name, schema.table name, or model name).
+// Unscoped fields apply to every generated model.
+func (w *Writer) addExtraFields(templateData *TemplateData) {
+	extraFields := LoadExtraFieldsFromMetadata(w.options.Metadata)
+	if len(extraFields) == 0 {
+		return
+	}
+
+	for _, model := range templateData.Models {
+		for _, ef := range extraFields {
+			if !extraFieldMatchesModel(ef, model) {
+				continue
+			}
+
+			fieldData := &FieldData{
+				Name:    resolveFieldNameCollision(ef.Name),
+				Type:    ef.Type,
+				BunTag:  ef.BunTag,
+				JSONTag: ef.JSONTag,
+				Comment: ef.Comment,
+			}
+			model.ExtraFields = append(model.ExtraFields, fieldData)
+		}
+	}
+}
+
+func extraFieldMatchesModel(field ExtraFieldConfig, model *ModelData) bool {
+	if field.TargetTable == "" {
+		return true
+	}
+
+	return field.TargetTable == model.TableNameOnly ||
+		field.TargetTable == model.TableName ||
+		field.TargetTable == model.Name
+}
+
 // WriteSchema writes a schema as Bun models
 func (w *Writer) WriteSchema(schema *models.Schema) error {
 	// Create a temporary database with just this schema
@@ -107,6 +144,9 @@ func (w *Writer) writeSingleFile(db *models.Database) error {
 		templateData.AddImport("\"fmt\"")
 	}
 
+	// Apply extra fields from generator config (issue #4)
+	w.addExtraFields(templateData)
+
 	// Finalize imports
 	templateData.FinalizeImports()
 
@@ -200,6 +240,9 @@ func (w *Writer) writeMultiFile(db *models.Database) error {
 				templateData.AddImport("\"fmt\"")
 			}
 
+			// Apply extra fields from generator config (issue #4)
+			w.addExtraFields(templateData)
+
 			// Finalize imports
 			templateData.FinalizeImports()
 

pkg/writers/bun/writer_test.go

@@ -855,6 +855,166 @@ func TestTypeMapper_BuildBunTag_StdlibArrayHasArrayTag(t *testing.T) {
 	}
 }
 
+func TestExtraFields_LoadFromMetadata(t *testing.T) {
+	tests := []struct {
+		name     string
+		metadata map[string]interface{}
+		expected int
+	}{
+		{
+			name:     "nil metadata",
+			metadata: nil,
+			expected: 0,
+		},
+		{
+			name: "no extra_fields key",
+			metadata: map[string]interface{}{
+				"generate_table_name": true,
+			},
+			expected: 0,
+		},
+		{
+			name: "empty array",
+			metadata: map[string]interface{}{
+				"extra_fields": []interface{}{},
+			},
+			expected: 0,
+		},
+		{
+			name: "JSON string format",
+			metadata: map[string]interface{}{
+				"extra_fields": `[{"name":"ThoughtCount","type":"int64","bun_tag":"thought_count,scanonly","json_tag":"thought_count"}]`,
+			},
+			expected: 1,
+		},
+		{
+			name: "structured format",
+			metadata: map[string]interface{}{
+				"extra_fields": []interface{}{
+					map[string]interface{}{
+						"name":     "ThoughtCount",
+						"type":     "int64",
+						"bun_tag":  "thought_count,scanonly",
+						"json_tag": "thought_count",
+					},
+				},
+			},
+			expected: 1,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			fields := LoadExtraFieldsFromMetadata(tt.metadata)
+			if len(fields) != tt.expected {
+				t.Errorf("expected %d fields, got %d", tt.expected, len(fields))
+			}
+		})
+	}
+}
+
+func TestExtraFields_InSingleFile(t *testing.T) {
+	table := models.InitTable("projects", "public")
+	table.Columns["id"] = &models.Column{
+		Name:         "id",
+		Type:         "bigint",
+		NotNull:      true,
+		IsPrimaryKey: true,
+	}
+	table.Columns["name"] = &models.Column{
+		Name:     "name",
+		Type:     "varchar",
+		Length:   255,
+		Sequence: 1,
+	}
+
+	opts := &writers.WriterOptions{
+		PackageName: "models",
+		OutputPath:  t.TempDir() + "/test.go",
+		Metadata: map[string]interface{}{
+			"extra_fields": `[{"name":"ThoughtCount","type":"int64","bun_tag":"thought_count,scanonly","json_tag":"thought_count"}]`,
+		},
+	}
+
+	writer := NewWriter(opts)
+	err := writer.WriteTable(table)
+	if err != nil {
+		t.Fatalf("WriteTable failed: %v", err)
+	}
+
+	content, _ := os.ReadFile(opts.OutputPath)
+	generated := string(content)
+
+	// Verify extra field is present with separator comment
+	expectations := []string{
+		"// --- Custom fields (managed by relspecgo generator config, issue #4) ---",
+		"ThoughtCount int64 `bun:\"thought_count,scanonly\" json:\"thought_count\"`",
+	}
+
+	for _, expected := range expectations {
+		if !strings.Contains(generated, expected) {
+			t.Errorf("Generated code missing: %q\nGenerated:\n%s", expected, generated)
+		}
+	}
+}
+
+func TestExtraFields_InMultiFile(t *testing.T) {
+	db := models.InitDatabase("testdb")
+	schema := models.InitSchema("public")
+
+	users := models.InitTable("users", "public")
+	users.Columns["id"] = &models.Column{
+		Name:         "id",
+		Type:         "bigint",
+		NotNull:      true,
+		IsPrimaryKey: true,
+	}
+	schema.Tables = append(schema.Tables, users)
+
+	posts := models.InitTable("posts", "public")
+	posts.Columns["id"] = &models.Column{
+		Name:         "id",
+		Type:         "bigint",
+		NotNull:      true,
+		IsPrimaryKey: true,
+	}
+	schema.Tables = append(schema.Tables, posts)
+
+	db.Schemas = append(db.Schemas, schema)
+
+	tmpDir := t.TempDir()
+	opts := &writers.WriterOptions{
+		PackageName: "models",
+		OutputPath:  tmpDir,
+		Metadata: map[string]interface{}{
+			"multi_file":   true,
+			"extra_fields": `[{"target_table":"users","name":"PostCount","type":"int64","bun_tag":"post_count,scanonly","json_tag":"post_count"}]`,
+		},
+	}
+
+	writer := NewWriter(opts)
+	err := writer.WriteDatabase(db)
+	if err != nil {
+		t.Fatalf("WriteDatabase failed: %v", err)
+	}
+
+	// Check users file has the extra field (matched by table name "users")
+	usersContent, _ := os.ReadFile(tmpDir + "/sql_public_users.go")
+	usersStr := string(usersContent)
+
+	if !strings.Contains(usersStr, "PostCount int64 `bun:\"post_count,scanonly\"") {
+		t.Errorf("Extra field not found in users file:\n%s", usersStr)
+	}
+
+	// Posts file should NOT have the extra field (name mismatch)
+	postsContent, _ := os.ReadFile(tmpDir + "/sql_public_posts.go")
+	postsStr := string(postsContent)
+
+	if strings.Contains(postsStr, "PostCount") {
+		t.Errorf("Extra field should not be in posts file:\n%s", postsStr)
+	}
+}
+
 func TestTypeMapper_BuildBunTag_PreservesExplicitTypeModifiers(t *testing.T) {
 	mapper := NewTypeMapper("")
 

test_data/asset-smoke/1_010_templates/assets.yaml

@@ -0,0 +1,6 @@
+- file: hello.md
+  call: |
+    INSERT INTO docs (name, content)
+    VALUES (:filename, :bytes::text)
+- file: logo.png
+  call: UPDATE branding SET logo = :bytes WHERE id = 1

test_data/asset-smoke/1_010_templates/hello.md

@@ -0,0 +1 @@
+# Hello World

test_data/asset-smoke/1_010_templates/logo.png

@@ -0,0 +1 @@
+PNG_PLACEHOLDER

test_data/asset-smoke/2_001_branding/assets.yaml

@@ -0,0 +1,4 @@
+- file: banner.txt
+  call: INSERT INTO banners (data) VALUES (:bytes)
+  params:
+    owner_id: "1"

test_data/asset-smoke/2_001_branding/banner.txt

@@ -0,0 +1 @@
+BANNER CONTENT