fix llm streaming

[tlgimenes]

Summary by cubic

Fixed real-time LLM streaming for OpenRouter by using the correct provider API and returning proper error responses. This prevents broken streams and surfaces accurate status, headers, and body on failures.

• Bug Fixes

  • Switched from openrouter.languageModel(modelId) to openrouter(modelId) for streaming.
  • Wrapped doStream in try/catch and mapped APICallError to Response with status, headers, and body.
  • Return 500 with a simple message for non-API errors.

• Dependencies

  • Updated @openrouter/ai-sdk-provider to ^1.5.4.
  • Updated @ai-sdk/provider to ^3.0.2 and @ai-sdk/provider-utils to ^4.0.4.
  • Refreshed lockfile to align transitive versions.

^{Written for commit efc81fb. Summary will update on new commits.}

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[cubic-dev-ai]

1 issue found across 3 files

Prompt for AI agents (all issues)

Check if these issues are valid — if so, understand the root cause of each and fix them.


<file name="openrouter/server/tools/llm-binding.ts">

<violation number="1" location="openrouter/server/tools/llm-binding.ts:471">
P2: Use `APICallError.isInstance(error)` instead of a custom symbol-based type guard. The AI SDK provides this static method specifically for type checking, and relying on internal symbols (`Symbol.for(&#39;vercel.ai.error&#39;)`) is fragile and could break with SDK updates.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

[cubic-dev-ai]

P2: Use APICallError.isInstance(error) instead of a custom symbol-based type guard. The AI SDK provides this static method specifically for type checking, and relying on internal symbols (Symbol.for('vercel.ai.error')) is fragile and could break with SDK updates.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At openrouter/server/tools/llm-binding.ts, line 471:

<comment>Use `APICallError.isInstance(error)` instead of a custom symbol-based type guard. The AI SDK provides this static method specifically for type checking, and relying on internal symbols (`Symbol.for(&#39;vercel.ai.error&#39;)`) is fragile and could break with SDK updates.</comment>

<file context>
@@ -467,6 +468,12 @@ const getUsageFromStream = (
   ];
 };
 
+const isAPICallError = (error: unknown): error is APICallError =&gt;
+  typeof error === &quot;object&quot; &amp;&amp;
+  error !== null &amp;&amp;
</file context>

Suggested change

	const isAPICallError = (error: unknown): error is APICallError =>
	typeof error === "object" &&
	error !== null &&
	Symbol.for("vercel.ai.error") in error &&
	Symbol.for("vercel.ai.error.AI_APICallError") in error;
	const isAPICallError = (error: unknown): error is APICallError =>
	APICallError.isInstance(error);