fix: classify openrouter json 404 model errors

Rewrites the stale branch on top of current `main` and preserves the original issue as regression coverage for the exact OpenRouter JSON 404 payload from openclaw#51571.

No production behavior changes are introduced here; current `main` already classifies this payload as `model_not_found`, and this merge locks that in across the shared matcher, failover classifier, and fallback loop.

Co-authored-by: 屈定 <mrdear@users.noreply.github.com>
Co-authored-by: Altay <altay@uinaf.dev>

Author: mrdear

src/agents/failover-error.test.ts

@@ -19,6 +19,8 @@ const GEMINI_RESOURCE_EXHAUSTED_MESSAGE =
   "RESOURCE_EXHAUSTED: Resource has been exhausted (e.g. check quota).";
 // OpenRouter 402 billing example: https://openrouter.ai/docs/api-reference/errors
 const OPENROUTER_CREDITS_MESSAGE = "Payment Required: insufficient credits";
+const OPENROUTER_MODEL_NOT_FOUND_PAYLOAD =
+  '{"error":{"message":"Healer Alpha was a stealth model revealed on March 18th as an early testing version of MiMo-V2-Omni. Find it here: https://openrouter.ai/xiaomi/mimo-v2-omni","code":404},"user_id":"user_33GTyP8uDSYYbaeBO48AGHXyuMC"}';
 const TOGETHER_MONTHLY_SPEND_CAP_MESSAGE =
   "The account associated with this API key has reached its maximum allowed monthly spending limit.";
 // Issue-backed Anthropic/OpenAI-compatible insufficient_quota payload under HTTP 400:
@@ -195,6 +197,14 @@ describe("failover-error", () => {
     ).toBe("model_not_found");
   });
 
+  it("classifies JSON-wrapped OpenRouter stealth-model 404s as model_not_found", () => {
+    expect(
+      resolveFailoverReasonFromError({
+        message: OPENROUTER_MODEL_NOT_FOUND_PAYLOAD,
+      }),
+    ).toBe("model_not_found");
+  });
+
   it("classifies generic model-does-not-exist messages as model_not_found", () => {
     expect(
       resolveFailoverReasonFromError({
@@ -569,6 +579,16 @@ describe("failover-error", () => {
     expect(err?.model).toBe("claude-opus-4-6");
   });
 
+  it("coerces JSON-wrapped OpenRouter stealth-model 404s into FailoverError", () => {
+    const err = coerceToFailoverError(OPENROUTER_MODEL_NOT_FOUND_PAYLOAD, {
+      provider: "openrouter",
+      model: "openrouter/healer-alpha",
+    });
+
+    expect(err?.reason).toBe("model_not_found");
+    expect(err?.status).toBe(404);
+  });
+
   it("maps overloaded to a 503 fallback status", () => {
     expect(resolveFailoverStatus("overloaded")).toBe(503);
   });

src/agents/live-model-errors.test.ts

@@ -6,10 +6,14 @@ import {
 
 describe("live model error helpers", () => {
   it("detects generic model-not-found messages", () => {
+    const openRouterJson404Payload =
+      '{"error":{"message":"Healer Alpha was a stealth model revealed on March 18th as an early testing version of MiMo-V2-Omni. Find it here: https://openrouter.ai/xiaomi/mimo-v2-omni","code":404},"user_id":"user_33GTyP8uDSYYbaeBO48AGHXyuMC"}';
+
     expect(isModelNotFoundErrorMessage("Model not found: openai/gpt-6")).toBe(true);
     expect(isModelNotFoundErrorMessage("model_not_found")).toBe(true);
     expect(isModelNotFoundErrorMessage("The model gpt-foo does not exist.")).toBe(true);
     expect(isModelNotFoundErrorMessage('{"code":404,"message":"model not found"}')).toBe(true);
+    expect(isModelNotFoundErrorMessage(openRouterJson404Payload)).toBe(true);
     expect(isModelNotFoundErrorMessage("model: MiniMax-M2.7-highspeed not found")).toBe(true);
     expect(
       isModelNotFoundErrorMessage("404 No endpoints found for deepseek/deepseek-r1:free."),
@@ -32,6 +36,9 @@ describe("live model error helpers", () => {
     expect(
       isModelNotFoundErrorMessage("The deployment does not exist or you do not have access."),
     ).toBe(false);
+    expect(isModelNotFoundErrorMessage('{"error":{"message":"Resource missing","code":404}}')).toBe(
+      false,
+    );
     expect(isModelNotFoundErrorMessage("request ended without sending any chunks")).toBe(false);
   });
 

src/agents/model-fallback.test.ts

@@ -22,6 +22,8 @@ vi.mock("../plugins/provider-runtime.js", () => ({
 }));
 
 const makeCfg = makeModelFallbackCfg;
+const OPENROUTER_MODEL_NOT_FOUND_PAYLOAD =
+  '{"error":{"message":"Healer Alpha was a stealth model revealed on March 18th as an early testing version of MiMo-V2-Omni. Find it here: https://openrouter.ai/xiaomi/mimo-v2-omni","code":404},"user_id":"user_33GTyP8uDSYYbaeBO48AGHXyuMC"}';
 
 function makeFallbacksOnlyCfg(): OpenClawConfig {
   return {
@@ -569,6 +571,26 @@ describe("runWithModelFallback", () => {
     expect(run.mock.calls[1]?.[1]).toBe("claude-haiku-3-5");
   });
 
+  it("falls back on JSON-wrapped OpenRouter stealth-model 404s", async () => {
+    const cfg = makeCfg();
+    const run = vi
+      .fn()
+      .mockRejectedValueOnce(new Error(OPENROUTER_MODEL_NOT_FOUND_PAYLOAD))
+      .mockResolvedValueOnce("ok");
+
+    const result = await runWithModelFallback({
+      cfg,
+      provider: "openrouter",
+      model: "openrouter/healer-alpha",
+      run,
+    });
+
+    expect(result.result).toBe("ok");
+    expect(run).toHaveBeenCalledTimes(2);
+    expect(run.mock.calls[1]?.[0]).toBe("openai");
+    expect(run.mock.calls[1]?.[1]).toBe("gpt-4.1-mini");
+  });
+
   it("warns when falling back due to model_not_found", async () => {
     setLoggerOverride({ level: "silent", consoleLevel: "warn" });
     const warnSpy = vi.spyOn(console, "warn").mockImplementation(() => {});