This is a comment left during a code review.
Path: src/agents/pi-embedded-runner-extraparams.test.ts
Line: 806-838

Comment:
**Missing coverage for `none` and `required` normalizations**

The new test only exercises the `{ type: "auto" }` → `"auto"` path, but the PR also adds `{ type: "none" }` → `"none"` and `{ type: "required" }` → `"required"` branches in `normalizeKimiCodingToolChoice`. Neither of those new branches is covered by a test, which means a future regression could go undetected.

Consider extending this test (or adding a parameterized table) to cover all three new cases — `"none"` and `"required"` alongside `"auto"` — so the behaviour is pinned:

```ts
it.each([
  ["auto", "auto"],
  ["none", "none"],
  ["required", "required"],
])("normalizes tool_choice {type: %s} to string %s for kimi-coding", (inputType, expected) => {
  const payloads: Record<string, unknown>[] = [];
  const baseStreamFn: StreamFn = (_model, _context, options) => {
    const payload: Record<string, unknown> = {
      tools: [{ name: "read", description: "Read file", input_schema: { type: "object", properties: {} } }],
      tool_choice: { type: inputType },
    };
    options?.onPayload?.(payload);
    payloads.push(payload);
    return {} as ReturnType<StreamFn>;
  };
  const agent = { streamFn: baseStreamFn };
  applyExtraParamsToAgent(agent, undefined, "kimi-coding", "k2p5", undefined, "low");
  const model = { api: "anthropic-messages", provider: "kimi-coding", id: "k2p5", baseUrl: "https://api.kimi.com/coding/" } as Model<"anthropic-messages">;
  void agent.streamFn?.(model, { messages: [] } as Context, {});
  expect(payloads[0]?.tool_choice).toBe(expected);
});
```

How can I resolve this? If you propose a fix, please make it concise.