diff --git a/pkg/autonomy/engine.go b/pkg/autonomy/engine.go
index f600de9..2a44858 100644
--- a/pkg/autonomy/engine.go
+++ b/pkg/autonomy/engine.go
@@ -52,6 +52,7 @@ type taskState struct {
 	RetryAfter       time.Time
 	ConsecutiveStall int
 	DedupeHits       int
+	ResourceKeys     []string
 }
 
 type Engine struct {
@@ -63,6 +64,7 @@ type Engine struct {
 	mu         sync.Mutex
 	state      map[string]*taskState
 	lastNotify map[string]time.Time
+	lockOwners map[string]string
 }
 
 func NewEngine(opts Options, msgBus *bus.MessageBus) *Engine {
@@ -100,6 +102,7 @@ func NewEngine(opts Options, msgBus *bus.MessageBus) *Engine {
 		taskStore:  NewTaskStore(opts.Workspace),
 		state:      map[string]*taskState{},
 		lastNotify: map[string]time.Time{},
+		lockOwners: map[string]string{},
 	}
 }
 
@@ -136,6 +139,7 @@ func (e *Engine) tick() {
 	if e.hasManualPause() {
 		for _, st := range e.state {
 			if st.Status == "running" {
+				e.releaseLocksLocked(st.ID)
 				st.Status = "waiting"
 				st.BlockReason = "manual_pause"
 				st.WaitingSince = now
@@ -150,6 +154,7 @@ func (e *Engine) tick() {
 	if e.hasRecentUserActivity(now) {
 		for _, st := range e.state {
 			if st.Status == "running" {
+				e.releaseLocksLocked(st.ID)
 				st.Status = "waiting"
 				st.BlockReason = "active_user"
 				st.WaitingSince = now
@@ -188,13 +193,14 @@ func (e *Engine) tick() {
 					}
 				}
 			}
-			e.state[t.ID] = &taskState{ID: t.ID, Content: t.Content, Priority: t.Priority, DueAt: t.DueAt, Status: status, RetryAfter: retryAfter, DedupeHits: t.DedupeHits}
+			e.state[t.ID] = &taskState{ID: t.ID, Content: t.Content, Priority: t.Priority, DueAt: t.DueAt, Status: status, RetryAfter: retryAfter, DedupeHits: t.DedupeHits, ResourceKeys: deriveResourceKeys(t.Content)}
 			continue
 		}
 		st.Content = t.Content
 		st.Priority = t.Priority
 		st.DueAt = t.DueAt
 		st.DedupeHits = t.DedupeHits
+		st.ResourceKeys = deriveResourceKeys(t.Content)
 		if st.Status == "completed" {
 			st.Status = "idle"
 		}
@@ -204,6 +210,7 @@ func (e *Engine) tick() {
 	for id, st := range e.state {
 		if _, ok := known[id]; !ok {
 			if st.Status != "completed" {
+				e.releaseLocksLocked(st.ID)
 				st.Status = "completed"
 				e.sendCompletionNotification(st)
 			}
@@ -237,6 +244,9 @@ func (e *Engine) tick() {
 			continue
 		}
 		if st.Status == "waiting" {
+			if st.BlockReason == "resource_lock" && !st.RetryAfter.IsZero() && now.Before(st.RetryAfter) {
+				continue
+			}
 			// Debounce waiting/resume flapping
 			if !st.WaitingSince.IsZero() && now.Sub(st.WaitingSince) < time.Duration(e.opts.WaitingResumeDebounceSec)*time.Second {
 				continue
@@ -249,6 +259,7 @@ func (e *Engine) tick() {
 			e.writeTriggerAudit("resume", st, reason)
 		}
 		if st.Status == "blocked" {
+			e.releaseLocksLocked(st.ID)
 			if !st.RetryAfter.IsZero() && now.Before(st.RetryAfter) {
 				continue
 			}
@@ -273,6 +284,14 @@ func (e *Engine) tick() {
 			}
 		}
 
+		if !e.tryAcquireLocksLocked(st) {
+			st.Status = "waiting"
+			st.BlockReason = "resource_lock"
+			st.WaitingSince = now
+			st.RetryAfter = now.Add(30 * time.Second)
+			e.writeTriggerAudit("waiting", st, "resource_lock")
+			continue
+		}
 		e.dispatchTask(st)
 		st.Status = "running"
 		st.BlockReason = ""
@@ -286,6 +305,61 @@ func (e *Engine) tick() {
 	e.persistStateLocked()
 }
 
+func (e *Engine) tryAcquireLocksLocked(st *taskState) bool {
+	if st == nil {
+		return false
+	}
+	keys := st.ResourceKeys
+	if len(keys) == 0 {
+		keys = []string{"task:" + st.ID}
+	}
+	for _, k := range keys {
+		if owner, ok := e.lockOwners[k]; ok && owner != "" && owner != st.ID {
+			return false
+		}
+	}
+	for _, k := range keys {
+		e.lockOwners[k] = st.ID
+	}
+	return true
+}
+
+func (e *Engine) releaseLocksLocked(taskID string) {
+	if strings.TrimSpace(taskID) == "" {
+		return
+	}
+	for k, v := range e.lockOwners {
+		if v == taskID {
+			delete(e.lockOwners, k)
+		}
+	}
+}
+
+func deriveResourceKeys(content string) []string {
+	content = strings.TrimSpace(strings.ToLower(content))
+	if content == "" {
+		return nil
+	}
+	keys := make([]string, 0, 4)
+	for _, token := range strings.Fields(content) {
+		t := strings.Trim(token, "`'\"()[]{}:;,，。！？")
+		if strings.Contains(t, "/") || strings.HasSuffix(t, ".go") || strings.HasSuffix(t, ".md") || strings.HasSuffix(t, ".json") || strings.HasSuffix(t, ".yaml") || strings.HasSuffix(t, ".yml") {
+			keys = append(keys, "file:"+t)
+		}
+	}
+	if len(keys) == 0 {
+		keys = append(keys, "scope:general")
+	}
+	sort.Strings(keys)
+	uniq := keys[:0]
+	for i, k := range keys {
+		if i == 0 || k != keys[i-1] {
+			uniq = append(uniq, k)
+		}
+	}
+	return append([]string(nil), uniq...)
+}
+
 type todoItem struct {
 	ID        string
 	Content   string