fix(openrouter): disable Claude Code tool search for OpenRouter sessions

apps/server/src/provider/openrouter/OpenRouterRuntime.test.ts

@@ -63,11 +63,23 @@ describe("OpenRouterRuntime", () => {
     expect(env.X_TITLE).toBe("T3 Code");
     // Claude Code only forwards headers through ANTHROPIC_CUSTOM_HEADERS.
     expect(env.ANTHROPIC_CUSTOM_HEADERS).toBe("HTTP-Referer: https://t3.chat\nX-Title: T3 Code");
+    // OpenRouter rejects deferred tools for non-Anthropic models.
+    expect(env.ENABLE_TOOL_SEARCH).toBe("false");
     expect(env.OR_SITE_URL).toBeUndefined();
     expect(env.OR_APP_NAME).toBeUndefined();
     expect(env.PATH).toBe("/usr/bin");
   });
 
+  it("keeps an explicit host tool-search choice", () => {
+    const settings = decodeOpenRouterSettings({ apiKey: "sk-or-test" });
+    const env = buildOpenRouterProcessEnv(settings, { ENABLE_TOOL_SEARCH: "true" });
+    expect(env.ENABLE_TOOL_SEARCH).toBe("true");
+
+    // A blank host value is not a choice, so the OpenRouter default applies.
+    const blank = buildOpenRouterProcessEnv(settings, { ENABLE_TOOL_SEARCH: "  " });
+    expect(blank.ENABLE_TOOL_SEARCH).toBe("false");
+  });
+
   it("clears inherited Anthropic credentials when settings apiKey is empty", () => {
     const settings = decodeOpenRouterSettings({
       apiKey: "",

apps/server/src/provider/openrouter/OpenRouterRuntime.ts

@@ -120,6 +120,17 @@ export function buildOpenRouterProcessEnv(
     next.ANTHROPIC_CUSTOM_HEADERS = customHeaders.join("\n");
   }
 
+  // Claude Code defaults to tool search, which omits tools from `tools[]` and
+  // refers to them with tool_reference blocks. OpenRouter's Anthropic-compatible
+  // endpoint rejects that for every non-Anthropic model ("Deferred custom tools
+  // are only supported on Anthropic models"), which kills the turn outright.
+  // "false" is Claude Code's own off switch (ENABLE_TOOL_SEARCH => "standard"
+  // mode). An explicit host value still wins, for proxies that do forward
+  // tool_reference blocks.
+  if (next.ENABLE_TOOL_SEARCH === undefined || next.ENABLE_TOOL_SEARCH.trim().length === 0) {
+    next.ENABLE_TOOL_SEARCH = "false";
+  }
+
   return next;
 }