registry: refresh schemas on tool_list and reload on tool_load

tool_load always re-reads the tool from disk (reload semantics).
tool_list calls RefreshLoaded to update schemas for all promoted tools.
Skills registry gets the same treatment: dynamic discovery, no cache.

skills/registry.go

@@ -4,9 +4,9 @@ package skills
 
 import (
 	"fmt"
-	"sort"
 	"os"
 	"path/filepath"
+	"sort"
 	"strings"
 	"sync"
 )
@@ -32,25 +32,33 @@ type SkillInfo struct {
 // Tracks which skills are loaded per session.
 type Registry struct {
 	mu       sync.RWMutex
-	global   map[string]SkillInfo
 	sessions map[string]map[string]bool // sessionID → skill name → loaded
 }
 
 func NewRegistry() *Registry {
 	return &Registry{
-		global:   make(map[string]SkillInfo),
 		sessions: make(map[string]map[string]bool),
 	}
 }
 
-// Discover scans the skills directory and registers all found skills.
+// Discover validates that the skills directory is readable.
+// Retained for backward compatibility; discovery is now dynamic.
 func (r *Registry) Discover() error {
+	dir := SkillsPath()
+	if _, err := os.ReadDir(dir); err != nil {
+		return fmt.Errorf("read skills dir %s: %w", dir, err)
+	}
+	return nil
+}
+
+// discover scans the skills directory and returns all found skills.
+func (r *Registry) discover() map[string]SkillInfo {
 	dir := SkillsPath()
 	entries, err := os.ReadDir(dir)
 	if err != nil {
-		return fmt.Errorf("read skills dir %s: %w", dir, err)
+		return nil
 	}
-	global := make(map[string]SkillInfo)
+	skills := make(map[string]SkillInfo)
 	for _, e := range entries {
 		if !e.IsDir() {
 			continue
@@ -67,24 +75,20 @@ func (r *Registry) Discover() error {
 		if err != nil {
 			continue
 		}
-		global[name] = SkillInfo{
+		skills[name] = SkillInfo{
 			Name:        meta.Name,
 			Description: meta.Description,
 			Dir:         skillDir,
 		}
 	}
-	r.mu.Lock()
-	r.global = global
-	r.mu.Unlock()
-	return nil
+	return skills
 }
 
 // Summaries returns all discovered skills.
 func (r *Registry) Summaries() []SkillInfo {
-	r.mu.RLock()
-	defer r.mu.RUnlock()
-	out := make([]SkillInfo, 0, len(r.global))
-	for _, info := range r.global {
+	skills := r.discover()
+	out := make([]SkillInfo, 0, len(skills))
+	for _, info := range skills {
 		out = append(out, info)
 	}
 	sort.Slice(out, func(i, j int) bool { return out[i].Name < out[j].Name })
@@ -93,10 +97,8 @@ func (r *Registry) Summaries() []SkillInfo {
 
 // Load marks a skill as loaded for the given session.
 func (r *Registry) Load(sessionID, name string) error {
-	r.mu.RLock()
-	_, exists := r.global[name]
-	r.mu.RUnlock()
-	if !exists {
+	skills := r.discover()
+	if _, exists := skills[name]; !exists {
 		return fmt.Errorf("skill not found: %s", name)
 	}
 	r.mu.Lock()
@@ -124,14 +126,15 @@ func (r *Registry) Unload(sessionID, name string) error {
 // Loaded returns skills currently loaded for a session.
 func (r *Registry) Loaded(sessionID string) []SkillInfo {
 	r.mu.RLock()
-	defer r.mu.RUnlock()
 	names, ok := r.sessions[sessionID]
+	r.mu.RUnlock()
 	if !ok {
 		return nil
 	}
+	skills := r.discover()
 	out := make([]SkillInfo, 0, len(names))
 	for name := range names {
-		if info, exists := r.global[name]; exists {
+		if info, exists := skills[name]; exists {
 			out = append(out, info)
 		}
 	}
@@ -142,9 +145,8 @@ func (r *Registry) Loaded(sessionID string) []SkillInfo {
 // SkillContent reads and returns the full content of a skill's SKILL.md file,
 // with front-matter stripped. Returns (content, error).
 func (r *Registry) SkillContent(name string) (string, error) {
-	r.mu.RLock()
-	info, exists := r.global[name]
-	r.mu.RUnlock()
+	skills := r.discover()
+	info, exists := skills[name]
 	if !exists {
 		return "", fmt.Errorf("skill not found: %s", name)
 	}

tools/tool.go

@@ -15,6 +15,13 @@ func ToolList(ctx context.Context, srv *toolsrv.Server, args json.RawMessage) (s
 	if reg == nil {
 		return "", fmt.Errorf("tool_list: no registry available")
 	}
+
+	// Refresh loaded tool schemas from disk so the model sees current definitions.
+	sid := srv.SessionID()
+	if sid != "" {
+		reg.RefreshLoaded(sid)
+	}
+
 	summaries := reg.Summaries()
 	if len(summaries) == 0 {
 		return "(no tools found)", nil

toolsrv/registry.go

@@ -80,10 +80,6 @@ func (r *Registry) Load(sessionID, name string) error {
 		r.sessions[sessionID] = make(map[string]ToolInfo)
 	}
 
-	if _, already := r.sessions[sessionID][name]; already {
-		return nil
-	}
-
 	r.sessions[sessionID][name] = tool
 	r.revisions[sessionID]++
 	return nil
@@ -124,6 +120,41 @@ func (r *Registry) Loaded(sessionID string) []ToolInfo {
 	return loaded
 }
 
+// RefreshLoaded re-reads all loaded tools from disk, updating their schemas
+// and metadata in place. Called from tool_list to keep schemas current.
+func (r *Registry) RefreshLoaded(sessionID string) {
+	r.mu.RLock()
+	sessionTools, ok := r.sessions[sessionID]
+	if !ok || len(sessionTools) == 0 {
+		r.mu.RUnlock()
+		return
+	}
+	names := make([]string, 0, len(sessionTools))
+	for name := range sessionTools {
+		names = append(names, name)
+	}
+	r.mu.RUnlock()
+
+	fresh := r.discover()
+
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	changed := false
+	for _, name := range names {
+		if tool, exists := fresh[name]; exists {
+			r.sessions[sessionID][name] = tool
+			changed = true
+		} else {
+			// Tool was removed from disk — unload it.
+			delete(r.sessions[sessionID], name)
+			changed = true
+		}
+	}
+	if changed {
+		r.revisions[sessionID]++
+	}
+}
+
 func (r *Registry) Lookup(sessionID, name string) (ToolInfo, bool) {
 	r.mu.RLock()
 	defer r.mu.RUnlock()