feat(ai-chat): expose requestId in OnChatMessageOptions

[dmmulroy]

Summary

• Add requestId: string to OnChatMessageOptions
• Pass the ID at all 3 onChatMessage call sites (initial request, tool continuation, approval continuation)

Problem

onChatMessage handlers cannot send error responses for pre-stream failures (e.g. body validation, auth checks) because they lack the request ID needed to tag CF_AGENT_USE_CHAT_RESPONSE messages. The client transport filters by data.id !== requestId, so messages without the correct ID are silently dropped.

The connection is accessible via getCurrentAgent().connection, but without the request ID there is no way to construct a message the client will accept.

Current workarounds are all bad:

• Throw → _tryCatchChat → onError → PartyServer swallows it. Client stream hangs forever.
• Return error Response → _reply sends it as a normal assistant text message (no error: true flag). Client renders a Zod error as if the assistant said it.
• safeParse + silent fallback → Bad input is invisible. Works but masks client bugs.

Solution

Expose the request ID that already exists at each call site:

Call site	ID source
Initial chat request	data.id (client-generated)
Tool continuation	continuationId (server-generated via nanoid())
Approval continuation	continuationId (server-generated via nanoid())

This lets onChatMessage send properly-tagged error responses:

async onChatMessage(onFinish, options) {
  const result = MySchema.safeParse(options?.body);
  if (!result.success) {
    const { connection } = getCurrentAgent();
    connection?.send(JSON.stringify({
      type: "cf_agent_use_chat_response",
      id: options.requestId,
      body: result.error.message,
      done: true,
      error: true,
    }));
    return; // no Response needed
  }
  // ... normal flow
}

Non-breaking: requestId is a new required field on OnChatMessageOptions, but this type is only constructed internally by AIChatAgent — user code receives it, never constructs it.

[changeset-bot]

🦋 Changeset detected

Latest commit: e3ee2fb

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@cloudflare/ai-chat	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/cloudflare/agents@977

npm i https://pkg.pr.new/cloudflare/agents/@cloudflare/ai-chat@977

npm i https://pkg.pr.new/cloudflare/agents/@cloudflare/codemode@977

npm i https://pkg.pr.new/cloudflare/agents/hono-agents@977

commit: e3ee2fb