fix(openrouter): restore attribution wrapper in extra params

[luoyanglang]

Summary

• restore the OpenRouter attribution wrapper in the applyExtraParamsToAgent() post-wrapper chain
• keep the existing pi-embedded-runner regression test green for OpenRouter attribution headers on chat-path models
• scope stays narrow: no changes to direct-completion attribution behavior, only the extra-params wrapper path

Validation

• pnpm.cmd exec vitest run src/agents/pi-embedded-runner-extraparams.test.ts
• pnpm.cmd exec oxlint src/agents/pi-embedded-runner/extra-params.ts src/agents/pi-embedded-runner-extraparams.test.ts

[greptile-apps]

Greptile Summary

Restores createOpenRouterSystemCacheWrapper to the applyPostPluginStreamWrappers post-plugin chain in extra-params.ts, ensuring Anthropic ephemeral cache markers are correctly applied for OpenRouter-routed Anthropic model IDs on the chat-path. The production fix is accurate and well-scoped.

Confidence Score: 5/5

Safe to merge; the code fix is correct and all remaining findings are P2.

The single P2 finding is a test-mock inaccuracy that is harmless for current test cases (no Anthropic model refs exercised). The production wrapper chain is correct after the fix.

src/agents/pi-embedded-runner-extraparams-openrouter.test.ts — the wrapProviderStreamFn mock wraps with createOpenRouterSystemCacheWrapper, which the real plugin does not; consider trimming it to just createOpenRouterWrapper.

Comments Outside Diff (1)

1. src/agents/pi-embedded-runner-extraparams-openrouter.test.ts, line 42 (link)

   Test mock wraps with createOpenRouterSystemCacheWrapper but production does not

   The production OpenRouter plugin (extensions/openrouter/stream.ts → wrapOpenRouterProviderStream) never calls createOpenRouterSystemCacheWrapper; it only applies routing injection and the "openrouter-thinking" stream-family hook (createOpenRouterWrapper). The cache wrapper is exclusively post-plugin, applied once by applyPostPluginStreamWrappers at extra-params.ts:395 — the line restored by this PR.

   With this fix in place, for any Anthropic model ref routed through OpenRouter, applyAnthropicEphemeralCacheControlMarkers will run twice: once from inside this mock's plugin layer and once from applyPostPluginStreamWrappers. That function mutates the payload in-place and is not idempotent — a second application on an already-mutated payload can produce incorrect cache-control structure.

   The current test models (deepseek/deepseek-r1, openrouter/auto, x-ai/grok-4.1-fast) all return false from isAnthropicModelRef(), so the double-application is a no-op today. However, the mock misrepresents the real wrapper chain and could produce silently double-mutated payloads if an Anthropic-on-OpenRouter test case is added later.

   Consider removing createOpenRouterSystemCacheWrapper from the mock's return value:

   Prompt To Fix With AI

   This is a comment left during a code review.
   Path: src/agents/pi-embedded-runner-extraparams-openrouter.test.ts
   Line: 42
   
   Comment:
   **Test mock wraps with `createOpenRouterSystemCacheWrapper` but production does not**
   
   The production OpenRouter plugin (`extensions/openrouter/stream.ts` → `wrapOpenRouterProviderStream`) never calls `createOpenRouterSystemCacheWrapper`; it only applies routing injection and the `"openrouter-thinking"` stream-family hook (`createOpenRouterWrapper`). The cache wrapper is exclusively post-plugin, applied once by `applyPostPluginStreamWrappers` at `extra-params.ts:395` — the line restored by this PR.
   
   With this fix in place, for any Anthropic model ref routed through OpenRouter, `applyAnthropicEphemeralCacheControlMarkers` will run twice: once from inside this mock's plugin layer and once from `applyPostPluginStreamWrappers`. That function mutates the payload in-place and is not idempotent — a second application on an already-mutated payload can produce incorrect cache-control structure.
   
   The current test models (`deepseek/deepseek-r1`, `openrouter/auto`, `x-ai/grok-4.1-fast`) all return `false` from `isAnthropicModelRef()`, so the double-application is a no-op today. However, the mock misrepresents the real wrapper chain and could produce silently double-mutated payloads if an Anthropic-on-OpenRouter test case is added later.
   
   Consider removing `createOpenRouterSystemCacheWrapper` from the mock's return value:
   
   
   How can I resolve this? If you propose a fix, please make it concise.

Prompt To Fix All With AI

This is a comment left during a code review.
Path: src/agents/pi-embedded-runner-extraparams-openrouter.test.ts
Line: 42

Comment:
**Test mock wraps with `createOpenRouterSystemCacheWrapper` but production does not**

The production OpenRouter plugin (`extensions/openrouter/stream.ts` → `wrapOpenRouterProviderStream`) never calls `createOpenRouterSystemCacheWrapper`; it only applies routing injection and the `"openrouter-thinking"` stream-family hook (`createOpenRouterWrapper`). The cache wrapper is exclusively post-plugin, applied once by `applyPostPluginStreamWrappers` at `extra-params.ts:395` — the line restored by this PR.

With this fix in place, for any Anthropic model ref routed through OpenRouter, `applyAnthropicEphemeralCacheControlMarkers` will run twice: once from inside this mock's plugin layer and once from `applyPostPluginStreamWrappers`. That function mutates the payload in-place and is not idempotent — a second application on an already-mutated payload can produce incorrect cache-control structure.

The current test models (`deepseek/deepseek-r1`, `openrouter/auto`, `x-ai/grok-4.1-fast`) all return `false` from `isAnthropicModelRef()`, so the double-application is a no-op today. However, the mock misrepresents the real wrapper chain and could produce silently double-mutated payloads if an Anthropic-on-OpenRouter test case is added later.

Consider removing `createOpenRouterSystemCacheWrapper` from the mock's return value:
```suggestion
      return createOpenRouterWrapper(streamFn, thinkingLevel);
```

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

_{Reviews (1): Last reviewed commit: "fix(openrouter): restore attribution wra..." | Re-trigger Greptile}