fix: allow skill_manage companion files

Squash merge PR #104 after validation.

internal/tools/skill_manage.go

@@ -4,9 +4,9 @@ import (
 	"context"
 	"crypto/sha256"
 	"fmt"
-	"io"
 	"log/slog"
 	"os"
+	"path"
 	"path/filepath"
 	"strings"
 	"time"
@@ -85,8 +85,8 @@ func (t *SkillManageTool) Name() string { return "skill_manage" }
 
 func (t *SkillManageTool) Description() string {
 	return "Create, patch, or delete your own skills from content strings. " +
-		"action=create: write a new skill from SKILL.md content (content string, no directory needed). " +
-		"action=patch: update an existing skill via find/replace (creates new immutable version). " +
+		"action=create: write a new skill from SKILL.md content and optional companion files. " +
+		"action=patch: update an existing skill via find/replace and/or companion files (creates new immutable version). " +
 		"action=delete: archive a skill so it is no longer discoverable. " +
 		"Security scanner rejects dangerous patterns. You can only manage skills you own."
 }
@@ -110,7 +110,7 @@ func (t *SkillManageTool) Parameters() map[string]any {
 			},
 			"find": map[string]any{
 				"type":        "string",
-				"description": "Exact text to find in the current SKILL.md. Required for patch unless only 'visibility' is being updated.",
+				"description": "Exact text to find in the current SKILL.md. Required for content patch unless only 'files' or 'visibility' is being updated.",
 			},
 			"replace": map[string]any{
 				"type":        "string",
@@ -121,6 +121,11 @@ func (t *SkillManageTool) Parameters() map[string]any {
 				"enum":        []string{skills.VisibilityPrivate, skills.VisibilityPublic},
 				"description": "Skill visibility. For create: defaults to 'private'. For patch: updates who can discover the skill without creating a new version.",
 			},
+			"files": map[string]any{
+				"type":                 "object",
+				"additionalProperties": map[string]any{"type": "string"},
+				"description":          "Optional companion files keyed by relative path under the skill root. SKILL.md must use 'content' or find/replace. Unsafe paths and system artifacts are rejected.",
+			},
 		},
 		"required": []string{"action"},
 	}
@@ -143,6 +148,13 @@ func (t *SkillManageTool) Execute(ctx context.Context, args map[string]any) *Res
 // maxSkillContentSize limits SKILL.md content to 100KB to prevent abuse.
 const maxSkillContentSize = 100 * 1024
 
+const maxManagedSkillFileSize = 2 << 20
+
+type managedSkillFile struct {
+	Path    string
+	Content []byte
+}
+
 // executeCreate writes a new skill from a SKILL.md content string.
 func (t *SkillManageTool) executeCreate(ctx context.Context, args map[string]any) *Result {
 	content, _ := args["content"].(string)
@@ -152,6 +164,13 @@ func (t *SkillManageTool) executeCreate(ctx context.Context, args map[string]any
 	if len(content) > maxSkillContentSize {
 		return ErrorResult(fmt.Sprintf("content too large (%d bytes, max %d)", len(content), maxSkillContentSize))
 	}
+	companionFiles, err := parseManagedSkillFiles(args["files"])
+	if err != nil {
+		return ErrorResult(err.Error())
+	}
+	if err := validateManagedSkillTotalSize(companionFiles); err != nil {
+		return ErrorResult(err.Error())
+	}
 
 	rawVisibility, _ := args["visibility"].(string)
 	if err := skills.ValidateVisibility(rawVisibility); err != nil {
@@ -191,6 +210,12 @@ func (t *SkillManageTool) executeCreate(ctx context.Context, args map[string]any
 	if err := os.MkdirAll(destDir, 0755); err != nil {
 		return ErrorResult(fmt.Sprintf("failed to create skill directory: %v", err))
 	}
+	cleanupDest := true
+	defer func() {
+		if cleanupDest {
+			_ = os.RemoveAll(destDir)
+		}
+	}()
 
 	// Write SKILL.md
 	contentBytes := []byte(content)
@@ -198,12 +223,18 @@ func (t *SkillManageTool) executeCreate(ctx context.Context, args map[string]any
 	if err := os.WriteFile(skillPath, contentBytes, 0644); err != nil {
 		return ErrorResult(fmt.Sprintf("failed to write SKILL.md: %v", err))
 	}
+	if err := writeManagedSkillFiles(destDir, companionFiles); err != nil {
+		return ErrorResult(fmt.Sprintf("failed to write companion files: %v", err))
+	}
 
 	// Hash + size
 	hasher := sha256.New()
 	hasher.Write(contentBytes)
 	fileHash := fmt.Sprintf("%x", hasher.Sum(nil))
-	fileSize := int64(len(contentBytes))
+	fileSize, err := dirSize(destDir)
+	if err != nil {
+		return ErrorResult(fmt.Sprintf("failed to calculate skill size: %v", err))
+	}
 
 	// DB insert — owner = actor (real sender) so skill belongs to the individual
 	// user rather than the group principal in group chats (#915).
@@ -227,6 +258,7 @@ func (t *SkillManageTool) executeCreate(ctx context.Context, args map[string]any
 	if err != nil {
 		return ErrorResult(fmt.Sprintf("failed to register skill: %v", err))
 	}
+	cleanupDest = false
 
 	slog.Info("skill_manage: created", "id", id, "slug", slug, "version", version, "owner", ownerID)
 
@@ -257,6 +289,9 @@ func (t *SkillManageTool) executeCreate(ctx context.Context, args map[string]any
 	}
 
 	result := fmt.Sprintf("Skill %q created.\n- Slug: %s\n- Version: %d", name, slug, version)
+	if len(companionFiles) > 0 {
+		result += fmt.Sprintf("\n- Companion files: %d", len(companionFiles))
+	}
 	if granted {
 		result += "\n- Granted to current agent"
 	}
@@ -273,15 +308,19 @@ func (t *SkillManageTool) executePatch(ctx context.Context, args map[string]any)
 	find, _ := args["find"].(string)
 	replace, _ := args["replace"].(string)
 	rawVisibility, _ := args["visibility"].(string)
+	companionFiles, filesErr := parseManagedSkillFiles(args["files"])
+	if filesErr != nil {
+		return ErrorResult(filesErr.Error())
+	}
 	if slug == "" {
 		return ErrorResult("slug is required for action=patch")
 	}
 	if err := skills.ValidateVisibility(rawVisibility); err != nil {
 		return ErrorResult(err.Error())
 	}
-	// Patch requires at least one of: content edit (find) or visibility change.
-	if find == "" && rawVisibility == "" {
-		return ErrorResult("patch requires either 'find' (content edit) or 'visibility' (metadata update)")
+	// Patch requires at least one of: content edit (find), file payload, or visibility change.
+	if find == "" && len(companionFiles) == 0 && rawVisibility == "" {
+		return ErrorResult("patch requires either 'find' (content edit), 'files' (companion files), or 'visibility' (metadata update)")
 	}
 
 	info, ok := t.skills.GetSkill(ctx, slug)
@@ -305,8 +344,8 @@ func (t *SkillManageTool) executePatch(ctx context.Context, args map[string]any)
 		return ErrorResult(fmt.Sprintf("cannot manage skill %q: you are not the owner", slug))
 	}
 
-	// Visibility-only patch path: no content change, no new version.
-	if find == "" && rawVisibility != "" {
+	// Visibility-only patch path: no content/files change, no new version.
+	if find == "" && len(companionFiles) == 0 && rawVisibility != "" {
 		skillID, err := uuid.Parse(info.ID)
 		if err != nil {
 			return ErrorResult(fmt.Sprintf("invalid skill ID in database: %v", err))
@@ -325,14 +364,43 @@ func (t *SkillManageTool) executePatch(ctx context.Context, args map[string]any)
 		return NewResult(fmt.Sprintf("Skill %q visibility set to %s.", slug, newVisibility))
 	}
 
-	// Read current SKILL.md from latest version
-	current, err := os.ReadFile(info.Path)
+	newVer, commitLock, lockErr := t.skills.GetNextVersionLocked(ctx, slug)
+	if lockErr != nil {
+		return ErrorResult(fmt.Sprintf("failed to lock version: %v", lockErr))
+	}
+	defer commitLock() //nolint:errcheck
+
+	latestInfo, ok := t.skills.GetSkill(ctx, slug)
+	if !ok {
+		return ErrorResult(fmt.Sprintf("skill %q not found or archived", slug))
+	}
+	if t.skills.IsSystemSkill(slug) {
+		return ErrorResult(fmt.Sprintf("cannot manage system skill %q", slug))
+	}
+	if !canManageSkill(ctx, t.skills, latestInfo) {
+		return ErrorResult(fmt.Sprintf("cannot manage skill %q: you are not the owner", slug))
+	}
+
+	existingFiles, err := collectExistingManagedSkillCompanionFiles(latestInfo.BaseDir)
+	if err != nil {
+		return ErrorResult(fmt.Sprintf("failed to inspect companion files: %v", err))
+	}
+	finalCompanionFiles := overlayManagedSkillFiles(existingFiles, companionFiles)
+	if err := validateManagedSkillTotalSize(finalCompanionFiles); err != nil {
+		return ErrorResult(err.Error())
+	}
+
+	// Read current SKILL.md from the latest version while the slug lock is held.
+	current, err := os.ReadFile(latestInfo.Path)
 	if err != nil {
 		return ErrorResult(fmt.Sprintf("failed to read current SKILL.md: %v", err))
 	}
 
-	patched := strings.Replace(string(current), find, replace, 1)
-	if patched == string(current) {
+	patched := string(current)
+	if find != "" {
+		patched = strings.Replace(patched, find, replace, 1)
+	}
+	if find != "" && patched == string(current) {
 		return NewResult("no change: find text not found in current SKILL.md")
 	}
 
@@ -342,16 +410,17 @@ func (t *SkillManageTool) executePatch(ctx context.Context, args map[string]any)
 		return ErrorResult(skills.FormatGuardViolations(violations))
 	}
 
-	oldVer := info.Version
-	newVer, commitLock, lockErr := t.skills.GetNextVersionLocked(ctx, slug)
-	if lockErr != nil {
-		return ErrorResult(fmt.Sprintf("failed to lock version: %v", lockErr))
-	}
-	defer commitLock() //nolint:errcheck
+	oldVer := latestInfo.Version
 	destDir := filepath.Join(t.tenantSkillsDir(ctx), slug, fmt.Sprintf("%d", newVer))
 	if err := os.MkdirAll(destDir, 0755); err != nil {
 		return ErrorResult(fmt.Sprintf("failed to create new version directory: %v", err))
 	}
+	cleanupDest := true
+	defer func() {
+		if cleanupDest {
+			_ = os.RemoveAll(destDir)
+		}
+	}()
 
 	// Write patched SKILL.md
 	patchedBytes := []byte(patched)
@@ -359,16 +428,18 @@ func (t *SkillManageTool) executePatch(ctx context.Context, args map[string]any)
 		return ErrorResult(fmt.Sprintf("failed to write patched SKILL.md: %v", err))
 	}
 
-	// Copy any companion files from old version (scripts, assets, etc.)
-	if err := copyOtherFiles(info.BaseDir, destDir); err != nil {
-		slog.Warn("skill_manage: failed to copy companion files", "error", err)
+	if err := writeManagedSkillFiles(destDir, finalCompanionFiles); err != nil {
+		return ErrorResult(fmt.Sprintf("failed to write companion files: %v", err))
 	}
 
 	// Hash + size
 	hasher := sha256.New()
 	hasher.Write(patchedBytes)
 	fileHash := fmt.Sprintf("%x", hasher.Sum(nil))
-	fileSize := int64(len(patchedBytes))
+	fileSize, err := dirSize(destDir)
+	if err != nil {
+		return ErrorResult(fmt.Sprintf("failed to calculate skill size: %v", err))
+	}
 
 	// DB update
 	skillID, err := uuid.Parse(info.ID)
@@ -388,14 +459,19 @@ func (t *SkillManageTool) executePatch(ctx context.Context, args map[string]any)
 	if err := t.skills.UpdateSkill(ctx, skillID, updates); err != nil {
 		return ErrorResult(fmt.Sprintf("failed to update skill in database: %v", err))
 	}
+	cleanupDest = false
 
-	slog.Info("skill_manage: patched", "slug", slug, "old_version", oldVer, "new_version", newVer)
+	slog.Info("skill_manage: patched", "slug", slug, "old_version", oldVer, "new_version", newVer, "companion_files", len(companionFiles))
 
 	if t.loader != nil {
 		t.loader.BumpVersion()
 	}
 
-	return NewResult(fmt.Sprintf("Skill %q patched. v%d → v%d. Changes active next turn.", slug, oldVer, newVer))
+	result := fmt.Sprintf("Skill %q patched. v%d → v%d. Changes active next turn.", slug, oldVer, newVer)
+	if len(companionFiles) > 0 {
+		result += fmt.Sprintf("\n- Companion files written: %d", len(companionFiles))
+	}
+	return NewResult(result)
 }
 
 // executeDelete archives a skill in the DB and moves its directory to .trash/.
@@ -455,53 +531,165 @@ func (t *SkillManageTool) executeDelete(ctx context.Context, args map[string]any
 // maxCopySize limits total companion file copy to 20MB (matching publish_skill).
 const maxCopySize = 20 << 20
 
-// copyOtherFiles copies all files from srcDir to dstDir except SKILL.md.
-// Used by patch to carry companion files (scripts, assets) into the new version directory.
-// Uses WalkDir (not Walk) so symlinks are detected via DirEntry.Type() before Stat follows them.
-// Enforces a 20MB total size limit.
-func copyOtherFiles(srcDir, dstDir string) error {
+func parseManagedSkillFiles(raw any) ([]managedSkillFile, error) {
+	if raw == nil {
+		return nil, nil
+	}
+	files, ok := raw.(map[string]any)
+	if !ok {
+		return nil, fmt.Errorf("files must be an object mapping relative paths to string content")
+	}
+	out := make([]managedSkillFile, 0, len(files))
+	for rawPath, rawContent := range files {
+		content, ok := rawContent.(string)
+		if !ok {
+			return nil, fmt.Errorf("files[%q] must be a string", rawPath)
+		}
+		cleanPath, err := validateManagedSkillFilePath(rawPath)
+		if err != nil {
+			return nil, err
+		}
+		if len(content) > maxManagedSkillFileSize {
+			return nil, fmt.Errorf("file %q too large (%d bytes, max %d)", cleanPath, len(content), maxManagedSkillFileSize)
+		}
+		out = append(out, managedSkillFile{Path: cleanPath, Content: []byte(content)})
+	}
+	return out, nil
+}
+
+func validateManagedSkillFilePath(rawPath string) (string, error) {
+	if rawPath == "" {
+		return "", fmt.Errorf("invalid file path %q: empty path", rawPath)
+	}
+	if strings.ContainsRune(rawPath, 0x00) {
+		return "", fmt.Errorf("invalid file path %q: null byte", rawPath)
+	}
+	if len(rawPath) >= 2 && rawPath[1] == ':' {
+		return "", fmt.Errorf("invalid file path %q: windows drive paths are not allowed", rawPath)
+	}
+	normalized := strings.ReplaceAll(rawPath, "\\", "/")
+	if strings.HasPrefix(normalized, "/") {
+		return "", fmt.Errorf("invalid file path %q: absolute paths are not allowed", rawPath)
+	}
+	for part := range strings.SplitSeq(normalized, "/") {
+		switch part {
+		case "..":
+			return "", fmt.Errorf("invalid file path %q: parent traversal is not allowed", rawPath)
+		case ".git":
+			return "", fmt.Errorf("invalid file path %q: system artifact paths are not allowed", rawPath)
+		}
+		if strings.HasPrefix(part, ".") {
+			return "", fmt.Errorf("invalid file path %q: hidden files are not allowed", rawPath)
+		}
+	}
+	cleanPath := path.Clean(normalized)
+	if cleanPath == "." || cleanPath == "SKILL.md" || strings.EqualFold(cleanPath, "SKILL.md") {
+		return "", fmt.Errorf("invalid file path %q: SKILL.md must be provided via content or find/replace", rawPath)
+	}
+	if strings.HasPrefix(cleanPath, "../") || cleanPath == ".." || strings.HasPrefix(cleanPath, "/") {
+		return "", fmt.Errorf("invalid file path %q: path escapes skill root", rawPath)
+	}
+	if skills.IsSystemArtifact(cleanPath) {
+		return "", fmt.Errorf("invalid file path %q: system artifact paths are not allowed", rawPath)
+	}
+	return cleanPath, nil
+}
+
+func collectExistingManagedSkillCompanionFiles(srcDir string) ([]managedSkillFile, error) {
+	var out []managedSkillFile
 	var totalSize int64
-	return filepath.WalkDir(srcDir, func(path string, d os.DirEntry, err error) error {
+	err := filepath.WalkDir(srcDir, func(filePath string, d os.DirEntry, err error) error {
 		if err != nil {
 			return err
 		}
-		// Skip symlinks — WalkDir exposes the raw type before following
 		if d.Type()&os.ModeSymlink != 0 {
 			return nil
 		}
-		rel, err := filepath.Rel(srcDir, path)
+		rel, err := filepath.Rel(srcDir, filePath)
 		if err != nil {
 			return err
 		}
+		rel = filepath.ToSlash(rel)
 		if rel == "." || rel == "SKILL.md" {
 			return nil
 		}
-		// Skip path traversal attempts
-		if strings.Contains(rel, "..") {
+		cleanPath := path.Clean(rel)
+		if cleanPath == "." || strings.HasPrefix(cleanPath, "../") || cleanPath == ".." || strings.HasPrefix(cleanPath, "/") {
+			return fmt.Errorf("existing companion file %q escapes skill root", rel)
+		}
+		if skills.IsSystemArtifact(cleanPath) {
+			if d.IsDir() {
+				return filepath.SkipDir
+			}
 			return nil
 		}
 		if d.IsDir() {
-			return os.MkdirAll(filepath.Join(dstDir, rel), 0755)
+			return nil
 		}
-		fi, err := d.Info()
+		info, err := d.Info()
 		if err != nil {
 			return err
 		}
-		totalSize += fi.Size()
+		totalSize += info.Size()
 		if totalSize > maxCopySize {
 			return fmt.Errorf("companion files exceed %d bytes limit", maxCopySize)
 		}
-		src, err := os.Open(path)
+		data, err := os.ReadFile(filePath)
 		if err != nil {
 			return err
 		}
-		defer src.Close()
-		dst, err := os.Create(filepath.Join(dstDir, rel))
-		if err != nil {
-			return err
-		}
-		defer dst.Close()
-		_, err = io.Copy(dst, src)
-		return err
+		out = append(out, managedSkillFile{Path: cleanPath, Content: data})
+		return nil
 	})
+	return out, err
+}
+
+func overlayManagedSkillFiles(existing, payload []managedSkillFile) []managedSkillFile {
+	byPath := make(map[string]managedSkillFile, len(existing)+len(payload))
+	order := make([]string, 0, len(existing)+len(payload))
+	for _, file := range existing {
+		if _, exists := byPath[file.Path]; !exists {
+			order = append(order, file.Path)
+		}
+		byPath[file.Path] = file
+	}
+	for _, file := range payload {
+		if _, exists := byPath[file.Path]; !exists {
+			order = append(order, file.Path)
+		}
+		byPath[file.Path] = file
+	}
+	out := make([]managedSkillFile, 0, len(order))
+	for _, filePath := range order {
+		out = append(out, byPath[filePath])
+	}
+	return out
+}
+
+func validateManagedSkillTotalSize(files []managedSkillFile) error {
+	var total int64
+	for _, file := range files {
+		total += int64(len(file.Content))
+		if total > maxCopySize {
+			return fmt.Errorf("companion files exceed %d bytes limit", maxCopySize)
+		}
+	}
+	return nil
+}
+
+func writeManagedSkillFiles(destDir string, files []managedSkillFile) error {
+	for _, file := range files {
+		destPath := filepath.Join(destDir, filepath.FromSlash(file.Path))
+		cleanDest := filepath.Clean(destPath)
+		if !strings.HasPrefix(cleanDest, destDir+string(filepath.Separator)) {
+			return fmt.Errorf("file %q escapes skill root", file.Path)
+		}
+		if err := os.MkdirAll(filepath.Dir(cleanDest), 0755); err != nil {
+			return err
+		}
+		if err := os.WriteFile(cleanDest, file.Content, 0644); err != nil {
+			return err
+		}
+	}
+	return nil
 }

internal/tools/skill_manage_files_test.go

@@ -0,0 +1,609 @@
+package tools
+
+import (
+	"context"
+	"maps"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/google/uuid"
+
+	"github.com/nextlevelbuilder/goclaw/internal/skills"
+	"github.com/nextlevelbuilder/goclaw/internal/store"
+)
+
+type skillManageFilesStore struct {
+	nextBySlug            map[string]int
+	skills                map[uuid.UUID]store.SkillInfo
+	owners                map[string]string
+	lastUpdates           map[uuid.UUID]map[string]any
+	beforeVersionLockHook func(slug string)
+}
+
+func newSkillManageFilesStore() *skillManageFilesStore {
+	return &skillManageFilesStore{
+		nextBySlug:  map[string]int{},
+		skills:      map[uuid.UUID]store.SkillInfo{},
+		owners:      map[string]string{},
+		lastUpdates: map[uuid.UUID]map[string]any{},
+	}
+}
+
+func skillManageFilesContext() context.Context {
+	ctx := store.WithTenantID(context.Background(), store.MasterTenantID)
+	ctx = store.WithUserID(ctx, "owner")
+	ctx = store.WithSenderID(ctx, "owner")
+	ctx = store.WithAgentID(ctx, uuid.New())
+	return ctx
+}
+
+func writeManagedSkillVersion(t *testing.T, root, slug string, version int, content string) string {
+	t.Helper()
+	dir := filepath.Join(root, "skills-store", slug, "1")
+	if version != 1 {
+		dir = filepath.Join(root, "skills-store", slug, "2")
+	}
+	if err := os.MkdirAll(dir, 0755); err != nil {
+		t.Fatalf("mkdir skill dir: %v", err)
+	}
+	if err := os.WriteFile(filepath.Join(dir, "SKILL.md"), []byte(content), 0644); err != nil {
+		t.Fatalf("write SKILL.md: %v", err)
+	}
+	return dir
+}
+
+func seedManagedSkill(t *testing.T, st *skillManageFilesStore, root, slug string, content string) (uuid.UUID, string) {
+	t.Helper()
+	dir := writeManagedSkillVersion(t, root, slug, 1, content)
+	id := uuid.New()
+	st.nextBySlug[slug] = 1
+	st.owners[slug] = "owner"
+	st.skills[id] = store.SkillInfo{
+		ID:         id.String(),
+		TenantID:   store.MasterTenantID.String(),
+		Name:       "Managed Skill",
+		Slug:       slug,
+		Path:       filepath.Join(dir, "SKILL.md"),
+		BaseDir:    dir,
+		Version:    1,
+		Status:     "active",
+		Enabled:    true,
+		Visibility: skills.VisibilityPrivate,
+		OwnerID:    "owner",
+	}
+	return id, dir
+}
+
+func validManagedSkillMarkdown(slug string) string {
+	return "---\nname: Managed Skill\nslug: " + slug + "\n---\nOriginal body\n"
+}
+
+func newSkillManageFilesTool(root string, st *skillManageFilesStore) *SkillManageTool {
+	return NewSkillManageTool(st, filepath.Join(root, "skills-store"), root, nil)
+}
+
+func TestSkillManagePatchFilesOnlyCreatesNewVersionWithReferenceFile(t *testing.T) {
+	t.Parallel()
+	root := t.TempDir()
+	st := newSkillManageFilesStore()
+	ctx := skillManageFilesContext()
+	seedManagedSkill(t, st, root, "managed-skill", validManagedSkillMarkdown("managed-skill"))
+
+	res := newSkillManageFilesTool(root, st).Execute(ctx, map[string]any{
+		"action": "patch",
+		"slug":   "managed-skill",
+		"files": map[string]any{
+			"references/ship-workflow.md": "# Ship\n",
+		},
+	})
+	if res.IsError {
+		t.Fatalf("patch returned error: %s", res.ForLLM)
+	}
+	if got := readTestFile(t, root, "skills-store/managed-skill/2/references/ship-workflow.md"); got != "# Ship\n" {
+		t.Fatalf("reference content = %q", got)
+	}
+	if got := st.latestBySlug("managed-skill").Version; got != 2 {
+		t.Fatalf("version = %d, want 2", got)
+	}
+}
+
+func TestSkillManagePatchFindReplaceAndFilesCopiesExistingCompanions(t *testing.T) {
+	t.Parallel()
+	root := t.TempDir()
+	st := newSkillManageFilesStore()
+	ctx := skillManageFilesContext()
+	_, v1Dir := seedManagedSkill(t, st, root, "managed-skill", validManagedSkillMarkdown("managed-skill"))
+	if err := os.MkdirAll(filepath.Join(v1Dir, "assets"), 0755); err != nil {
+		t.Fatalf("mkdir assets: %v", err)
+	}
+	if err := os.WriteFile(filepath.Join(v1Dir, "assets/logo.txt"), []byte("logo"), 0644); err != nil {
+		t.Fatalf("write asset: %v", err)
+	}
+
+	res := newSkillManageFilesTool(root, st).Execute(ctx, map[string]any{
+		"action":  "patch",
+		"slug":    "managed-skill",
+		"find":    "Original body",
+		"replace": "Updated body",
+		"files": map[string]any{
+			"references/ship-workflow.md": "# Ship\n",
+		},
+	})
+	if res.IsError {
+		t.Fatalf("patch returned error: %s", res.ForLLM)
+	}
+	if got := readTestFile(t, root, "skills-store/managed-skill/2/SKILL.md"); !strings.Contains(got, "Updated body") {
+		t.Fatalf("patched SKILL.md missing update: %q", got)
+	}
+	if got := readTestFile(t, root, "skills-store/managed-skill/2/assets/logo.txt"); got != "logo" {
+		t.Fatalf("copied asset = %q", got)
+	}
+	if got := readTestFile(t, root, "skills-store/managed-skill/2/references/ship-workflow.md"); got != "# Ship\n" {
+		t.Fatalf("reference content = %q", got)
+	}
+}
+
+func TestSkillManagePatchCopiesExistingHiddenCompanions(t *testing.T) {
+	t.Parallel()
+	root := t.TempDir()
+	st := newSkillManageFilesStore()
+	ctx := skillManageFilesContext()
+	_, v1Dir := seedManagedSkill(t, st, root, "managed-skill", validManagedSkillMarkdown("managed-skill"))
+	paths := map[string]string{
+		".env.example":                       "TOKEN=\n",
+		".github/workflows/check.yml":        "name: check\n",
+		"references/ship-workflow.md":        "# Ship\n",
+		"references/nested/.keep-example.md": "keep\n",
+	}
+	for relPath, content := range paths {
+		fullPath := filepath.Join(v1Dir, filepath.FromSlash(relPath))
+		if err := os.MkdirAll(filepath.Dir(fullPath), 0755); err != nil {
+			t.Fatalf("mkdir %s: %v", relPath, err)
+		}
+		if err := os.WriteFile(fullPath, []byte(content), 0644); err != nil {
+			t.Fatalf("write %s: %v", relPath, err)
+		}
+	}
+
+	res := newSkillManageFilesTool(root, st).Execute(ctx, map[string]any{
+		"action": "patch",
+		"slug":   "managed-skill",
+		"files": map[string]any{
+			"references/new.md": "# New\n",
+		},
+	})
+	if res.IsError {
+		t.Fatalf("patch returned error: %s", res.ForLLM)
+	}
+	for relPath, want := range paths {
+		got := readTestFile(t, root, filepath.Join("skills-store/managed-skill/2", filepath.ToSlash(relPath)))
+		if got != want {
+			t.Fatalf("copied %s = %q, want %q", relPath, got, want)
+		}
+	}
+}
+
+func TestSkillManagePatchCopiesExistingLargeCompanionUnderTotalLimit(t *testing.T) {
+	t.Parallel()
+	root := t.TempDir()
+	st := newSkillManageFilesStore()
+	ctx := skillManageFilesContext()
+	_, v1Dir := seedManagedSkill(t, st, root, "managed-skill", validManagedSkillMarkdown("managed-skill"))
+	largeContent := strings.Repeat("x", maxManagedSkillFileSize+1)
+	largePath := filepath.Join(v1Dir, "assets", "large.txt")
+	if err := os.MkdirAll(filepath.Dir(largePath), 0755); err != nil {
+		t.Fatalf("mkdir large asset: %v", err)
+	}
+	if err := os.WriteFile(largePath, []byte(largeContent), 0644); err != nil {
+		t.Fatalf("write large asset: %v", err)
+	}
+
+	res := newSkillManageFilesTool(root, st).Execute(ctx, map[string]any{
+		"action": "patch",
+		"slug":   "managed-skill",
+		"files": map[string]any{
+			"references/new.md": "# New\n",
+		},
+	})
+	if res.IsError {
+		t.Fatalf("patch returned error: %s", res.ForLLM)
+	}
+	if got := readTestFile(t, root, "skills-store/managed-skill/2/assets/large.txt"); got != largeContent {
+		t.Fatalf("large asset length = %d, want %d", len(got), len(largeContent))
+	}
+}
+
+func TestSkillManagePatchReloadsLatestVersionAfterLock(t *testing.T) {
+	t.Parallel()
+	root := t.TempDir()
+	st := newSkillManageFilesStore()
+	ctx := skillManageFilesContext()
+	id, _ := seedManagedSkill(t, st, root, "managed-skill", validManagedSkillMarkdown("managed-skill"))
+	st.beforeVersionLockHook = func(slug string) {
+		if slug != "managed-skill" {
+			return
+		}
+		v2Dir := writeManagedSkillVersion(t, root, slug, 2, validManagedSkillMarkdown(slug))
+		firstPath := filepath.Join(v2Dir, "references", "first.md")
+		if err := os.MkdirAll(filepath.Dir(firstPath), 0755); err != nil {
+			t.Fatalf("mkdir concurrent reference: %v", err)
+		}
+		if err := os.WriteFile(firstPath, []byte("# First\n"), 0644); err != nil {
+			t.Fatalf("write concurrent reference: %v", err)
+		}
+		skill := st.skills[id]
+		skill.Version = 2
+		skill.BaseDir = v2Dir
+		skill.Path = filepath.Join(v2Dir, "SKILL.md")
+		st.skills[id] = skill
+		st.nextBySlug[slug] = 2
+		st.beforeVersionLockHook = nil
+	}
+
+	res := newSkillManageFilesTool(root, st).Execute(ctx, map[string]any{
+		"action": "patch",
+		"slug":   "managed-skill",
+		"files": map[string]any{
+			"references/second.md": "# Second\n",
+		},
+	})
+	if res.IsError {
+		t.Fatalf("patch returned error: %s", res.ForLLM)
+	}
+	if got := readTestFile(t, root, "skills-store/managed-skill/3/references/first.md"); got != "# First\n" {
+		t.Fatalf("first concurrent reference = %q", got)
+	}
+	if got := readTestFile(t, root, "skills-store/managed-skill/3/references/second.md"); got != "# Second\n" {
+		t.Fatalf("second reference = %q", got)
+	}
+}
+
+func TestSkillManagePatchFilesOverlayExistingCompanion(t *testing.T) {
+	t.Parallel()
+	root := t.TempDir()
+	st := newSkillManageFilesStore()
+	ctx := skillManageFilesContext()
+	_, v1Dir := seedManagedSkill(t, st, root, "managed-skill", validManagedSkillMarkdown("managed-skill"))
+	if err := os.MkdirAll(filepath.Join(v1Dir, "references"), 0755); err != nil {
+		t.Fatalf("mkdir references: %v", err)
+	}
+	if err := os.WriteFile(filepath.Join(v1Dir, "references/guide.md"), []byte("old"), 0644); err != nil {
+		t.Fatalf("write reference: %v", err)
+	}
+
+	res := newSkillManageFilesTool(root, st).Execute(ctx, map[string]any{
+		"action": "patch",
+		"slug":   "managed-skill",
+		"files": map[string]any{
+			"references/guide.md": "new",
+		},
+	})
+	if res.IsError {
+		t.Fatalf("patch returned error: %s", res.ForLLM)
+	}
+	if got := readTestFile(t, root, "skills-store/managed-skill/2/references/guide.md"); got != "new" {
+		t.Fatalf("overlaid reference content = %q", got)
+	}
+}
+
+func TestSkillManageCreateWritesCompanionFiles(t *testing.T) {
+	t.Parallel()
+	root := t.TempDir()
+	st := newSkillManageFilesStore()
+	ctx := skillManageFilesContext()
+
+	res := newSkillManageFilesTool(root, st).Execute(ctx, map[string]any{
+		"action":  "create",
+		"content": validManagedSkillMarkdown("new-skill"),
+		"files": map[string]any{
+			"references/guide.md": "# Guide\n",
+		},
+	})
+	if res.IsError {
+		t.Fatalf("create returned error: %s", res.ForLLM)
+	}
+	if got := readTestFile(t, root, "skills-store/new-skill/1/references/guide.md"); got != "# Guide\n" {
+		t.Fatalf("reference content = %q", got)
+	}
+}
+
+func TestSkillManageVisibilityOnlyPatchDoesNotCreateNewVersion(t *testing.T) {
+	t.Parallel()
+	root := t.TempDir()
+	st := newSkillManageFilesStore()
+	ctx := skillManageFilesContext()
+	id, _ := seedManagedSkill(t, st, root, "managed-skill", validManagedSkillMarkdown("managed-skill"))
+
+	res := newSkillManageFilesTool(root, st).Execute(ctx, map[string]any{
+		"action":     "patch",
+		"slug":       "managed-skill",
+		"visibility": skills.VisibilityPublic,
+	})
+	if res.IsError {
+		t.Fatalf("patch returned error: %s", res.ForLLM)
+	}
+	if got := st.latestBySlug("managed-skill").Version; got != 1 {
+		t.Fatalf("version = %d, want unchanged v1", got)
+	}
+	if _, err := os.Stat(filepath.Join(root, "skills-store/managed-skill/2")); !os.IsNotExist(err) {
+		t.Fatalf("version 2 dir exists after visibility-only patch: err=%v", err)
+	}
+	if got := st.lastUpdates[id]["visibility"]; got != skills.VisibilityPublic {
+		t.Fatalf("visibility update = %v, want public", got)
+	}
+}
+
+func TestSkillManageFilesRejectUnsafePathsBeforeCreatingVersion(t *testing.T) {
+	t.Parallel()
+	cases := []string{
+		"/abs.md",
+		"../escape.md",
+		`C:/escape.md`,
+		"references/ok\x00.md",
+		".git/config",
+		".env",
+		"references/.secret",
+		"__MACOSX/x",
+		".DS_Store",
+		"SKILL.md",
+	}
+	for _, relPath := range cases {
+		t.Run(relPath, func(t *testing.T) {
+			t.Parallel()
+			root := t.TempDir()
+			st := newSkillManageFilesStore()
+			ctx := skillManageFilesContext()
+			seedManagedSkill(t, st, root, "managed-skill", validManagedSkillMarkdown("managed-skill"))
+
+			res := newSkillManageFilesTool(root, st).Execute(ctx, map[string]any{
+				"action": "patch",
+				"slug":   "managed-skill",
+				"files": map[string]any{
+					relPath: "bad",
+				},
+			})
+			if !res.IsError {
+				t.Fatalf("patch succeeded for unsafe path %q: %s", relPath, res.ForLLM)
+			}
+			if !strings.Contains(res.ForLLM, "invalid file path") {
+				t.Fatalf("error = %q, want invalid file path", res.ForLLM)
+			}
+			if _, err := os.Stat(filepath.Join(root, "skills-store/managed-skill/2")); !os.IsNotExist(err) {
+				t.Fatalf("version 2 dir exists after rejected path: err=%v", err)
+			}
+		})
+	}
+}
+
+func TestSkillManageFilesRejectNonStringPayload(t *testing.T) {
+	t.Parallel()
+	root := t.TempDir()
+	st := newSkillManageFilesStore()
+	ctx := skillManageFilesContext()
+	seedManagedSkill(t, st, root, "managed-skill", validManagedSkillMarkdown("managed-skill"))
+
+	res := newSkillManageFilesTool(root, st).Execute(ctx, map[string]any{
+		"action": "patch",
+		"slug":   "managed-skill",
+		"files": map[string]any{
+			"references/guide.md": map[string]any{"nested": "no"},
+		},
+	})
+	if !res.IsError {
+		t.Fatalf("patch succeeded with non-string payload: %s", res.ForLLM)
+	}
+	if !strings.Contains(res.ForLLM, "must be a string") {
+		t.Fatalf("error = %q, want string validation", res.ForLLM)
+	}
+	if _, err := os.Stat(filepath.Join(root, "skills-store/managed-skill/2")); !os.IsNotExist(err) {
+		t.Fatalf("version 2 dir exists after rejected payload: err=%v", err)
+	}
+}
+
+func TestSkillManageFilesRejectOversizePayloadBeforeCreatingVersion(t *testing.T) {
+	t.Parallel()
+	root := t.TempDir()
+	st := newSkillManageFilesStore()
+	ctx := skillManageFilesContext()
+	seedManagedSkill(t, st, root, "managed-skill", validManagedSkillMarkdown("managed-skill"))
+
+	res := newSkillManageFilesTool(root, st).Execute(ctx, map[string]any{
+		"action": "patch",
+		"slug":   "managed-skill",
+		"files": map[string]any{
+			"references/too-large.md": strings.Repeat("x", maxManagedSkillFileSize+1),
+		},
+	})
+	if !res.IsError {
+		t.Fatalf("patch succeeded with oversize payload: %s", res.ForLLM)
+	}
+	if !strings.Contains(res.ForLLM, "too large") {
+		t.Fatalf("error = %q, want size validation", res.ForLLM)
+	}
+	if _, err := os.Stat(filepath.Join(root, "skills-store/managed-skill/2")); !os.IsNotExist(err) {
+		t.Fatalf("version 2 dir exists after rejected payload: err=%v", err)
+	}
+}
+
+func TestSkillManagePatchFindMissWithFilesDoesNotCreateVersion(t *testing.T) {
+	t.Parallel()
+	root := t.TempDir()
+	st := newSkillManageFilesStore()
+	ctx := skillManageFilesContext()
+	seedManagedSkill(t, st, root, "managed-skill", validManagedSkillMarkdown("managed-skill"))
+
+	res := newSkillManageFilesTool(root, st).Execute(ctx, map[string]any{
+		"action":  "patch",
+		"slug":    "managed-skill",
+		"find":    "missing text",
+		"replace": "replacement",
+		"files": map[string]any{
+			"references/guide.md": "# Guide\n",
+		},
+	})
+	if res.IsError {
+		t.Fatalf("patch returned error: %s", res.ForLLM)
+	}
+	if !strings.Contains(res.ForLLM, "no change") {
+		t.Fatalf("result = %q, want no-change message", res.ForLLM)
+	}
+	if _, err := os.Stat(filepath.Join(root, "skills-store/managed-skill/2")); !os.IsNotExist(err) {
+		t.Fatalf("version 2 dir exists after missing find: err=%v", err)
+	}
+}
+
+func readTestFile(t *testing.T, root, rel string) string {
+	t.Helper()
+	data, err := os.ReadFile(filepath.Join(root, filepath.FromSlash(rel)))
+	if err != nil {
+		t.Fatalf("read %s: %v", rel, err)
+	}
+	return string(data)
+}
+
+func (s *skillManageFilesStore) latestBySlug(slug string) store.SkillInfo {
+	var latest store.SkillInfo
+	for _, skill := range s.skills {
+		if skill.Slug == slug && skill.Version > latest.Version {
+			latest = skill
+		}
+	}
+	return latest
+}
+
+func (s *skillManageFilesStore) ListSkills(context.Context) []store.SkillInfo { return nil }
+func (s *skillManageFilesStore) LoadSkill(context.Context, string) (string, bool) {
+	return "", false
+}
+func (s *skillManageFilesStore) LoadForContext(context.Context, []string) string { return "" }
+func (s *skillManageFilesStore) BuildSummary(context.Context, []string) string   { return "" }
+func (s *skillManageFilesStore) GetSkill(_ context.Context, slug string) (*store.SkillInfo, bool) {
+	for _, skill := range s.skills {
+		if skill.Slug == slug && skill.Status != "deleted" {
+			copy := skill
+			return &copy, true
+		}
+	}
+	return nil, false
+}
+func (s *skillManageFilesStore) FilterSkills(context.Context, []string) []store.SkillInfo {
+	return nil
+}
+func (s *skillManageFilesStore) Version() int64 { return 0 }
+func (s *skillManageFilesStore) BumpVersion()   {}
+func (s *skillManageFilesStore) Dirs() []string { return nil }
+func (s *skillManageFilesStore) CreateSkillManaged(ctx context.Context, p store.SkillCreateParams) (uuid.UUID, error) {
+	id := uuid.New()
+	version := p.Version
+	if version == 0 {
+		version = s.nextBySlug[p.Slug] + 1
+	}
+	if version > s.nextBySlug[p.Slug] {
+		s.nextBySlug[p.Slug] = version
+	}
+	s.owners[p.Slug] = p.OwnerID
+	s.skills[id] = store.SkillInfo{
+		ID:          id.String(),
+		TenantID:    store.MasterTenantID.String(),
+		Name:        p.Name,
+		Slug:        p.Slug,
+		Description: derefString(p.Description),
+		Path:        filepath.Join(p.FilePath, "SKILL.md"),
+		BaseDir:     p.FilePath,
+		Version:     version,
+		Status:      "active",
+		Enabled:     true,
+		Visibility:  p.Visibility,
+		OwnerID:     p.OwnerID,
+	}
+	return id, nil
+}
+func (s *skillManageFilesStore) UpdateSkill(_ context.Context, id uuid.UUID, updates map[string]any) error {
+	skill, ok := s.skills[id]
+	if !ok {
+		return nil
+	}
+	if version, ok := updates["version"].(int); ok {
+		skill.Version = version
+		if version > s.nextBySlug[skill.Slug] {
+			s.nextBySlug[skill.Slug] = version
+		}
+	}
+	if filePath, ok := updates["file_path"].(string); ok {
+		skill.BaseDir = filePath
+		skill.Path = filepath.Join(filePath, "SKILL.md")
+	}
+	if visibility, ok := updates["visibility"].(string); ok {
+		skill.Visibility = visibility
+	}
+	s.lastUpdates[id] = maps.Clone(updates)
+	s.skills[id] = skill
+	return nil
+}
+func (s *skillManageFilesStore) DeleteSkill(context.Context, uuid.UUID) error       { return nil }
+func (s *skillManageFilesStore) ToggleSkill(context.Context, uuid.UUID, bool) error { return nil }
+func (s *skillManageFilesStore) GetSkillByID(_ context.Context, id uuid.UUID) (store.SkillInfo, bool) {
+	info, ok := s.skills[id]
+	return info, ok
+}
+func (s *skillManageFilesStore) GetSkillOwnerID(context.Context, uuid.UUID) (string, bool) {
+	return "", false
+}
+func (s *skillManageFilesStore) GetSkillOwnerIDBySlug(_ context.Context, slug string) (string, bool) {
+	owner, ok := s.owners[slug]
+	return owner, ok
+}
+func (s *skillManageFilesStore) GetNextVersion(_ context.Context, slug string) int {
+	return s.nextBySlug[slug] + 1
+}
+func (s *skillManageFilesStore) GetNextVersionLocked(_ context.Context, slug string) (int, func() error, error) {
+	if s.beforeVersionLockHook != nil {
+		s.beforeVersionLockHook(slug)
+	}
+	return s.GetNextVersion(context.Background(), slug), func() error { return nil }, nil
+}
+func (s *skillManageFilesStore) GetSkillHashBySlug(context.Context, string) (string, int, bool) {
+	return "", 0, false
+}
+func (s *skillManageFilesStore) IsSystemSkill(string) bool                       { return false }
+func (s *skillManageFilesStore) ListAllSkills(context.Context) []store.SkillInfo { return nil }
+func (s *skillManageFilesStore) ListAllSystemSkills(context.Context) []store.SkillInfo {
+	return nil
+}
+func (s *skillManageFilesStore) ListSystemSkillDirs(context.Context) map[string]string {
+	return nil
+}
+func (s *skillManageFilesStore) StoreMissingDeps(context.Context, uuid.UUID, []string) error {
+	return nil
+}
+func (s *skillManageFilesStore) GrantToAgent(context.Context, uuid.UUID, uuid.UUID, int, string, ...bool) error {
+	return nil
+}
+func (s *skillManageFilesStore) RevokeFromAgent(context.Context, uuid.UUID, uuid.UUID) error {
+	return nil
+}
+func (s *skillManageFilesStore) GrantToUser(context.Context, uuid.UUID, string, string) error {
+	return nil
+}
+func (s *skillManageFilesStore) RevokeFromUser(context.Context, uuid.UUID, string) error { return nil }
+func (s *skillManageFilesStore) ListWithGrantStatus(context.Context, uuid.UUID) ([]store.SkillWithGrantStatus, error) {
+	return nil, nil
+}
+func (s *skillManageFilesStore) ListAgentGrantsForSkill(context.Context, uuid.UUID) ([]store.SkillAgentGrantInfo, error) {
+	return nil, nil
+}
+func (s *skillManageFilesStore) AgentCanManageSkill(context.Context, uuid.UUID, uuid.UUID) (bool, error) {
+	return false, nil
+}
+func (s *skillManageFilesStore) GetSkillFilePath(context.Context, uuid.UUID) (string, string, int, bool, bool) {
+	return "", "", 0, false, false
+}
+
+func derefString(v *string) string {
+	if v == nil {
+		return ""
+	}
+	return *v
+}