Interception extension points — the typed-Decision surface a hook programs against

Run pre-step policy at every proposed step. The loop opens the turn before the initial claim and decision, so rejection closes a durable blocked turn with no step or model-visible message. A tool continuation with no newly claimed input still submits an empty batch, allowing per-request context producers to add logged messages to that exact request. On enter, the loop opens the step and appends the returned batch as user/message events before request derivation. Each claimed follow-up remains the sole direct prompt in its turn under the one-send-one-turn simplification.

Post-tool additionalContexts and asynchronous injections enter the active-batch FIFO and append when that batch settles. content/feedback shape the result execute() returns, but each context is a separate sourced user/message, and a single step or composite tool can produce many. Appending context immediately would interleave result(c1) → context → result(c2) or place nested context before its outer result, breaking tool-call/result adjacency. ToolRunContext.deferContext() therefore collects nested-dispatch context through failures, execute() surfaces the ordered array on ToolExecutionResult, and the loop accepts it into the same FIFO as agent.inject() calls made during execution. The FIFO appends after every recorded result when the batch settles, including before an interrupted turn closes. An accepted outer call preserves deferred contexts before decision contexts; an outer block discards deferred contexts and exposes only contexts explicitly supplied by the blocking decision.

A stopping listener requests continuation through the steering channel, so the next step's top-of-loop drain records it as steering for the continued turn — next-step steering within the SAME turn, not a next-turn prompt.

在每个拟议步骤运行 pre-step 策略。 循环会在首次领取和决策之前打开轮次，因此 reject 会关闭一个持久、blocked 且不含步骤或模型可见消息的轮次。即使工具续步没有新取得所有权的输入，也会提交空批次，使逐请求上下文生产方可以把带日志的消息加入这一次请求。enter 时，循环先开启步骤，再把返回批次作为 user/message 追加，然后派生请求。依照一次 send 对应一个轮次的简化，每个已领取 follow-up 仍是其轮次中唯一的直接提示词。

工具执行后的 additionalContexts 与异步注入进入活跃批次 FIFO，并在该批次结算时追加。 content/feedback 塑造 execute() 返回的结果，但每项上下文都是一条独立的带来源 user/message，而单个步骤或组合工具可以产生许多上下文。立即追加上下文会产生 result(c1) → context → result(c2) 的交错，或把嵌套上下文放在外层结果之前，破坏工具调用／工具结果邻接性。因此 ToolRunContext.deferContext() 会在失败路径上也收集嵌套调度上下文，execute() 在 ToolExecutionResult 上暴露有序数组，循环再把它接纳到与执行期间 agent.inject() 调用相同的 FIFO 中。FIFO 在批次结算时，在所有已记录结果之后追加，其中也包括被中断轮次关闭之前。被接受的外层调用将 deferred contexts 保留在 decision contexts 之前；被外层阻止时则丢弃 deferred contexts，只暴露阻止 decision 显式提供的上下文。

stopping 监听器通过 steering 通道请求继续执行，使得下一步骤在循环顶部排空时将其记录为当前轮次的 steering——同一轮次内的下一步骤 steering，而非下一轮次的提示词。