openrouter:web_search reports provider as OpenAI for Anthropic model requests

[richardwu]

Summary

When using @openrouter/ai-sdk-provider with the native OpenRouter web search tool, web search appears to work, but the returned provider metadata reports OpenAI even when the requested model is Anthropic.

For example, this request uses:

model: openrouter.chat("anthropic/claude-opus-4.6")

but after the stream completes:

(await result.providerMetadata)?.openrouter?.provider

returns:

"OpenAI"

The issue is not that web search fails. The issue is that provider metadata says the provider was OpenAI for an Anthropic model request when openrouter:web_search is enabled.

Environment

• @openrouter/ai-sdk-provider: 2.2.3
• ai: 6.0.97
• Runtime: Bun / Node-style server runtime
• API: streamText with openrouter.chat(...)
• Native server tool: openrouter:web_search

Repro

import { createOpenRouter } from "@openrouter/ai-sdk-provider";
import { streamText, stepCountIs } from "ai";

const openrouter = createOpenRouter({ apiKey: process.env.OPENROUTER_API_KEY! });

const result = streamText({
  model: openrouter.chat("anthropic/claude-opus-4.6"),
  messages: [
    {
      role: "user",
      content: "Use web search to find the latest OpenRouter routing docs and cite what you used.",
    },
  ],
  stopWhen: stepCountIs(1),
  providerOptions: {
    openrouter: {
      tools: [
        {
          type: "openrouter:web_search",
          parameters: {
            engine: "auto",
            max_results: 5,
            max_total_results: 15,
          },
        },
      ],
      tool_choice: "auto",
    },
  },
});

await result.consumeStream();
console.log({
  provider: (await result.providerMetadata)?.openrouter?.provider,
  text: await result.text,
});

Actual output

The exact text varies, but the provider metadata reports OpenAI:

{
  provider: "OpenAI",
  text: "Here's a comprehensive summary of the latest OpenRouter routing documentation..."
}

The generated text includes web-search-based citations, so the tool appears to be working.

Expected behavior

For a request using openrouter.chat("anthropic/claude-opus-4.6"), provider metadata should not report OpenAI unless OpenRouter intentionally routes Anthropic model requests with web search through an OpenAI-backed provider.

If that routing is intentional, it would be helpful for the provider metadata or docs to make that explicit. Otherwise, this looks like incorrect provider metadata when openrouter:web_search is enabled.

[mattapperson]

Thanks so much for the detailed report, and for flagging the ambiguity around whether this is routing-related!

We tried to reproduce this and, on the current versions, we're seeing the provider correctly attributed as Anthropic rather than OpenAI. Here's what we ran:

SDK path (your exact code) with @openrouter/ai-sdk-provider 2.9.1 and ai 6.0.207, using streamText with anthropic/claude-opus-4.6 and the openrouter:web_search tool, then reading result.providerMetadata:

provider: "Anthropic"

Raw API (curl, stream: true) for the same model with the web plugin enabled: across all 16 SSE chunks, every one reported "provider":"Anthropic" — none ever emitted "OpenAI".

For context, the SDK doesn't compute or override the provider name at all — it passes the provider field straight through from the API response — so the value you see comes directly from the backend. Since we can't reproduce the OpenAI attribution today, it looks like it may already be resolved (possibly a backend fix that landed after you filed), but we'd love to confirm rather than assume.

To help us pin it down, could you share:

1. The exact @openrouter/ai-sdk-provider and ai versions that exhibited OpenAI.
2. A minimal runnable snippet (model id + the full providerOptions/tools you used).
3. If possible, the raw SSE chunks or response from the failing run showing provider: "OpenAI".

That'll let us tell whether it's fully gone or intermittent. Appreciate your patience!

— the OpenRouter SDK team