Agents: test per-agent model fallbacks override

src/agents/model-fallback.test.ts

@@ -156,6 +156,74 @@ describe("runWithModelFallback", () => {
     ]);
   });
 
+  it("uses fallbacksOverride instead of agents.defaults.model.fallbacks", async () => {
+    const cfg = {
+      agents: {
+        defaults: {
+          model: {
+            fallbacks: ["openai/gpt-5.2"],
+          },
+        },
+      },
+    } as ClawdbotConfig;
+
+    const calls: Array<{ provider: string; model: string }> = [];
+
+    const res = await runWithModelFallback({
+      cfg,
+      provider: "anthropic",
+      model: "claude-opus-4-5",
+      fallbacksOverride: ["openai/gpt-4.1"],
+      run: async (provider, model) => {
+        calls.push({ provider, model });
+        if (provider === "anthropic") {
+          throw new Error("primary failed");
+        }
+        if (provider === "openai" && model === "gpt-4.1") {
+          return "ok";
+        }
+        throw new Error(`unexpected candidate: ${provider}/${model}`);
+      },
+    });
+
+    expect(res.result).toBe("ok");
+    expect(calls).toEqual([
+      { provider: "anthropic", model: "claude-opus-4-5" },
+      { provider: "openai", model: "gpt-4.1" },
+    ]);
+  });
+
+  it("treats an empty fallbacksOverride as disabling global fallbacks", async () => {
+    const cfg = {
+      agents: {
+        defaults: {
+          model: {
+            fallbacks: ["openai/gpt-5.2"],
+          },
+        },
+      },
+    } as ClawdbotConfig;
+
+    const calls: Array<{ provider: string; model: string }> = [];
+
+    await expect(
+      runWithModelFallback({
+        cfg,
+        provider: "anthropic",
+        model: "claude-opus-4-5",
+        fallbacksOverride: [],
+        run: async (provider, model) => {
+          calls.push({ provider, model });
+          throw new Error("primary failed");
+        },
+      }),
+    ).rejects.toThrow("primary failed");
+
+    expect(calls).toEqual([
+      { provider: "anthropic", model: "claude-opus-4-5" },
+    ]);
+  });
+
   it("falls back on missing API key errors", async () => {
     const cfg = makeCfg();
     const run = vi