fix(tui): route prompts by next-step capability

packages/core/agent-loop/src/agent.ts

@@ -53,7 +53,7 @@ export class ReactLoopAgent implements Agent {
   /** Whether observers see a running interval; consecutive turns share it. */
   private busy = false
   /** Whether next-step input belongs to the current admission or open turn. */
-  private acceptingNextStep = false
+  acceptsNextStep = false
   /** Abort owner for the current admission or turn. */
   private abort: AbortController | undefined
   /** Coalesced retry capability scoped to the active request-error waterfall. */
@@ -99,7 +99,7 @@ export class ReactLoopAgent implements Agent {
     const { target, wakeup } = options
     const id = AgentMessageId(randomUUID())
     if (target === 'next-step' && !wakeup) {
-      if (this.acceptingNextStep) {
+      if (this.acceptsNextStep) {
         this.outbox.push({ content, source })
         return id
       }
@@ -107,7 +107,7 @@ export class ReactLoopAgent implements Agent {
       return id
     }
 
-    const placement: InboxPlacement = target === 'next-step' && this.acceptingNextStep ? 'steering' : 'queued'
+    const placement: InboxPlacement = target === 'next-step' && this.acceptsNextStep ? 'steering' : 'queued'
     const message: AgentMessage = {
       id,
       content,
@@ -215,7 +215,7 @@ export class ReactLoopAgent implements Agent {
 
     const admission = new AbortController()
     this.abort = admission
-    this.acceptingNextStep = true
+    this.acceptsNextStep = true
     // Claimed admission is part of the running interval: it is cancellable
     // activity, so observers (and their cancel routing) must see it.
     if (!this.busy) {
@@ -257,7 +257,7 @@ export class ReactLoopAgent implements Agent {
       // still owns the slot here and releasing it unconditionally is exact.
       this.abort = undefined
       if (admitted === undefined) {
-        this.acceptingNextStep = false
+        this.acceptsNextStep = false
         // A synchronously aborted admission would otherwise publish idle
         // inside send()'s own synchronous extent, before any post-send
         // subscriber could observe the transition.
@@ -284,7 +284,7 @@ export class ReactLoopAgent implements Agent {
     if (this.abort !== undefined) throw new Error(`agent "${this.id}" is already running`)
     const controller = new AbortController()
     this.abort = controller
-    this.acceptingNextStep = true
+    this.acceptsNextStep = true
     if (!this.busy) {
       this.busy = true
       emitAgentEvent(this.loopCtx, this, 'agent/status', 'running')
@@ -390,7 +390,7 @@ export class ReactLoopAgent implements Agent {
       // Every step-close happens before this point on both success and
       // failure paths (step(), the request-failed branch, the catch), so the
       // finally owes only the turn boundary.
-      this.acceptingNextStep = false
+      this.acceptsNextStep = false
       try {
         if (this.turnOpen) {
           // Re-entrant turn/end listeners must route new input to a later turn.

packages/core/agent-loop/tests/contract-regressions.spec.ts

@@ -338,6 +338,7 @@ describe('steering from late extension points is never stranded', () => {
       if (event.type === 'turn/start') turns.push(event.data.turn)
       if (event.type === 'turn/end' && !steeredOnce) {
         steeredOnce = true
+        expect(agent.acceptsNextStep).toBe(false)
         agent.steer({ content: [{ type: 'text', text: 'too late for this turn' }], source: { kind: 'user' } })
       }
     })

packages/core/agent-loop/tests/interception.spec.ts

@@ -183,6 +183,7 @@ describe('agent/prompt-submit', () => {
     send(agent, 'admitted prompt')
     await entered.promise
     expect(agent.status).toBe('running')
+    expect(agent.acceptsNextStep).toBe(true)
     expect(events(agent).some(event => event.type === 'turn/start')).toBe(false)
 
     agent.inject({
@@ -195,6 +196,7 @@ describe('agent/prompt-submit', () => {
 
     decision.resolve({ kind: 'allow' })
     await idle
+    expect(agent.acceptsNextStep).toBe(false)
 
     const staged = events(agent).filter(event =>
       event.type === 'turn/start' || event.type === 'user/message' || event.type === 'steering/message')
@@ -230,6 +232,7 @@ describe('agent/prompt-submit', () => {
     const blockedIdle = waitForIdle(ctx, agent)
     send(agent, 'blocked prompt')
     await entered.promise
+    expect(agent.acceptsNextStep).toBe(true)
     agent.inject({
       content: [{ type: 'text', text: 'staged context' }],
       source: { kind: 'plugin', plugin: 'test' },
@@ -238,6 +241,7 @@ describe('agent/prompt-submit', () => {
     decision.resolve({ kind: 'block', reason: 'policy' })
     await blockedIdle
 
+    expect(agent.acceptsNextStep).toBe(false)
     expect(events(agent)).toEqual([])
     expect(adapter.requests).toEqual([])
 

packages/core/agent/src/types.ts

@@ -147,6 +147,12 @@ export interface Agent {
   readonly session: Session
   /** The current lifecycle state, mirrored on every `agent/status` transition. */
   readonly status: AgentStatus
+  /**
+   * Whether a `next-step` send currently stages for prompt admission or the
+   * open turn. Unlike {@link status}, this excludes admission exit and turn
+   * settlement, when a waking `next-step` send becomes a queued follow-up.
+   */
+  readonly acceptsNextStep: boolean
   /** Agent-scoped context; its contributions are agent-local, unwind on disposal, and reject registration afterward. */
   readonly ctx: Context
 

packages/core/agent/tests/agent.spec.ts

@@ -17,11 +17,12 @@ import type {
 
 function stubAgent(rawId: string, overrides: Partial<Agent> = {}): Agent {
   const id = SessionId(rawId)
-  return {
+  const agent: Agent = {
     id,
     options: {},
     session: new Session(id),
     status: 'idle',
+    acceptsNextStep: false,
     ctx: new Context(),
     send: () => AgentMessageId('stub'),
     followup: () => AgentMessageId('stub'),
@@ -30,8 +31,8 @@ function stubAgent(rawId: string, overrides: Partial<Agent> = {}): Agent {
     cancel() {},
     retry() {},
     whenIdle() { return Promise.resolve() },
-    ...overrides,
   }
+  return Object.assign(agent, overrides)
 }
 
 describe('AgentRegistry', () => {