9p: add statewait/usagewait/ctxszwait/cwdwait; rename enqueue/dequeue

*wait files block on read until the corresponding value changes, then
return the new value. enqueue/dequeue renamed to fifo.in/fifo.out.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

README.md

@@ -53,16 +53,20 @@ ollie/
       chat              read:  cumulative conversation history
       ctl               write: stop | <command>
       ctxsz             read:  estimated context size vs context window
-      dequeue           read:  pop the next queued prompt
-      enqueue           write: queue a prompt for later execution
+      ctxszwait         read:  blocks until ctxsz changes; returns new value
+      cwd               r/w:   working directory for tool execution
+      cwdwait           read:  blocks until cwd changes; returns new value
+      fifo.in           write: queue a prompt for later execution
+      fifo.out          read:  pop the next queued prompt
       mcp               read:  MCP server list
       model             r/w:   active model name
       models            read:  available models from the backend
       prompt            write: submit a prompt to the agent
       state             read:  current agent state (idle, thinking, calling: <tool>)
+      statewait         read:  blocks until state changes; returns new value
       systemprompt      read:  fully rendered system prompt for this session
       usage             read:  token counts (input, output, requests; [estimated] if not reported by backend)
-      cwd               r/w:   working directory for tool execution and system prompt
+      usagewait         read:  blocks until usage changes; returns new value
   sk/                   dir:   skills (r/w, from OLLIE_SKILLS_PATH or ~/.config/ollie/skills/)
     <name>.md           r/w:   skill SKILL.md content
   t/                    dir:   tool scripts (r/w, backed by ~/.config/ollie/tools/)

internal/p9/server.go

@@ -14,8 +14,8 @@
 //	        {session-id}/           rm -r to kill session; mv to rename
 //	            ctl         (write) session control: stop, kill, rn, compact, clear
 //	            prompt      (write) submit a prompt to the agent
-//	            enqueue     (write) queue a prompt for later execution
-//	            dequeue     (read)  pop the next queued prompt
+//	            fifo.in     (write) queue a prompt for later execution
+//	            fifo.out    (read)  pop the next queued prompt
 //	            chat        (r/w)   cumulative chat history; write to save a transcript to tr/
 //	            state       (read)  current agent state
 //	            backend     (r/w)   active backend name
@@ -718,8 +718,8 @@ func (s *Server) read(cs *connState, fc *plan9.Fcall) *plan9.Fcall {
 				plog.Debug("Rread session not found: %s", parts[1])
 				return &plan9.Fcall{Type: plan9.Rread, Tag: fc.Tag, Count: 0}
 			}
-			// dequeue: non-zero offset is the trailing EOF read after a successful pop.
-			if parts[2] == "dequeue" && fc.Offset > 0 {
+			// fifo.out: non-zero offset is the trailing EOF read after a successful pop.
+			if parts[2] == "fifo.out" && fc.Offset > 0 {
 				return &plan9.Fcall{Type: plan9.Rread, Tag: fc.Tag, Count: 0}
 			}
 			content, err := store.Get(parts[2])
@@ -945,7 +945,7 @@ func (s *Server) isAsyncWrite(path string) bool {
 		return false
 	}
 	switch pathBase(path) {
-	case "prompt", "enqueue", "ctl":
+	case "prompt", "fifo.in", "ctl":
 		return true
 	}
 	return false
@@ -1449,9 +1449,9 @@ func (s *Server) makeStat(path string) plan9.Dir {
 		}
 	} else {
 		switch base {
-		case "ctl", "prompt", "enqueue":
+		case "ctl", "prompt", "fifo.in":
 			mode = 0200
-		case "chat", "state", "usage", "ctxsz", "models", "mcp", "dequeue":
+		case "chat", "state", "usage", "ctxsz", "models", "mcp", "fifo.out":
 			mode = 0444
 		case "backend", "agent", "model", "cwd":
 			mode = 0666

internal/p9/sessionfilestore.go

@@ -18,17 +18,21 @@ var sessionFileList = []struct {
 }{
 	{"ctl", 0200},
 	{"prompt", 0200},
-	{"enqueue", 0200},
-	{"dequeue", 0444},
+	{"fifo.in", 0200},
+	{"fifo.out", 0444},
 	{"chat", 0666},
 	{"offset", 0444},
 	{"state", 0444},
+	{"statewait", 0444},
 	{"backend", 0666},
 	{"agent", 0666},
 	{"model", 0666},
 	{"cwd", 0666},
+	{"cwdwait", 0444},
 	{"usage", 0444},
+	{"usagewait", 0444},
 	{"ctxsz", 0444},
+	{"ctxszwait", 0444},
 	{"models", 0444},
 	{"mcp", 0444},
 	{"systemprompt", 0444},
@@ -66,6 +70,8 @@ func (s *SessionFileStore) Stat(name string) (os.FileInfo, error) {
 				s.sess.mu.RLock()
 				size = int64(len(s.sess.chatLog))
 				s.sess.mu.RUnlock()
+			case "statewait", "usagewait", "ctxszwait", "cwdwait":
+				// Blocking reads; size is unknown until resolved.
 			default:
 				size = int64(len(s.content(name)))
 			}
@@ -85,12 +91,40 @@ func (s *SessionFileStore) Get(name string) ([]byte, error) {
 		return data, nil
 	case "offset":
 		return []byte(s.content("offset")), nil
-	case "dequeue":
+	case "fifo.out":
 		item, ok := s.sess.core.PopQueue()
 		if !ok {
 			return nil, nil
 		}
 		return []byte(item), nil
+	case "statewait":
+		current := s.sess.core.State()
+		v, ok := s.sess.core.WaitChange(s.sess.ctx, agent.WatchState, current)
+		if !ok {
+			return nil, nil
+		}
+		return []byte(v + "\n"), nil
+	case "usagewait":
+		current := s.sess.core.Usage()
+		v, ok := s.sess.core.WaitChange(s.sess.ctx, agent.WatchUsage, current)
+		if !ok {
+			return nil, nil
+		}
+		return []byte(v + "\n"), nil
+	case "ctxszwait":
+		current := s.sess.core.CtxSz()
+		v, ok := s.sess.core.WaitChange(s.sess.ctx, agent.WatchCtxSz, current)
+		if !ok {
+			return nil, nil
+		}
+		return []byte(v + "\n"), nil
+	case "cwdwait":
+		current := s.sess.core.CWD()
+		v, ok := s.sess.core.WaitChange(s.sess.ctx, agent.WatchCWD, current)
+		if !ok {
+			return nil, nil
+		}
+		return []byte(v + "\n"), nil
 	default:
 		for _, f := range sessionFileList {
 			if f.name == name {
@@ -113,7 +147,7 @@ func (s *SessionFileStore) Put(name string, data []byte) error {
 	case "prompt":
 		s.sess.core.Submit(s.sess.ctx, input, s.makePublish())
 
-	case "enqueue":
+	case "fifo.in":
 		s.sess.core.Queue(input)
 
 	case "ctl":