refactor(agent-loop): simplify observable state machine

packages/hooks/hooks-codex/src/index.ts

@@ -15,7 +15,7 @@
 import { readFileSync } from 'node:fs'
 import type { Context } from 'cordis'
 import z from 'schemastery'
-import type { AdditionalContext, Agent, ContinuationDecision, PromptDecision } from '@deepseek-ai/dsh-agent'
+import type { AdditionalContext, Agent, PromptDecision } from '@deepseek-ai/dsh-agent'
 import type { ContentBlock, MessageSource } from '@deepseek-ai/dsh-llm'
 import type {} from '@deepseek-ai/dsh-session-persistence'
 import type { PostToolDecision, PreToolDecision, ToolExecution, ToolExecutionResult } from '@deepseek-ai/dsh-tools'
@@ -236,11 +236,12 @@ export function apply(ctx: Context, config: Config): void {
     }
   })
 
-  // Stop → ContinuationDecision. A blocking Stop hook forces continuation.
+  // A blocking Stop hook steers at the stopping boundary, which makes the
+  // machine observe pending input and run another step.
   // TODO(stop-loop-guard): Codex supplies `stop_hook_active` so a Stop hook can
   // avoid continuing the same turn indefinitely. It is always false here, so an
   // unconditionally blocking hook force-continues every step until it self-limits.
-  ctx.on('agent/turn-continuation', async (agent, turn, _default, signal, next): Promise<ContinuationDecision> => {
+  ctx.on('agent/stopping', async (agent, turn, signal): Promise<void> => {
     const merged = await runPoint('Stop', '', { ...turnBase(ctx, agent, 'Stop', model), stop_hook_active: false, last_assistant_message: null }, { agent, turn, signal })
     /* jscpd:ignore-end */
     if (merged.decision === 'deny') {
@@ -248,9 +249,8 @@ export function apply(ctx: Context, config: Config): void {
       // empty stderr) still forces it — fall back to a generic steering line
       // rather than letting the turn stop.
       const text = merged.reason ?? 'continue: blocked by Stop hook'
-      return { action: 'continue', reason: { content: [{ type: 'text', text }], source: PLUGIN_SOURCE } }
+      agent.steer([{ type: 'text', text }], { source: PLUGIN_SOURCE })
     }
-    return next()
   })
 }