diff --git a/src/agents/model-scan.test.ts b/src/agents/model-scan.test.ts
index d69445324..7919a8bf6 100644
--- a/src/agents/model-scan.test.ts
+++ b/src/agents/model-scan.test.ts
@@ -85,4 +85,40 @@ describe("scanOpenRouterModels", () => {
       }
     }
   });
+
+  it("avoids double-prefixing openrouter/ in modelRef", async () => {
+    const fetchImpl = createFetchFixture({
+      data: [
+        {
+          id: "openrouter/auto",
+          name: "OpenRouter Auto",
+          context_length: 128_000,
+          max_completion_tokens: 4096,
+          supported_parameters: ["tools"],
+          modality: "text",
+          pricing: { prompt: "0", completion: "0" },
+        },
+        {
+          id: "meta-llama/llama-3.3-70b:free",
+          name: "Llama 3.3 70B",
+          context_length: 8_192,
+          supported_parameters: [],
+          modality: "text",
+          pricing: { prompt: "0", completion: "0" },
+        },
+      ],
+    });
+
+    const results = await scanOpenRouterModels({
+      fetchImpl,
+      probe: false,
+    });
+
+    // IDs are normalized (prefix stripped), but modelRefs are correct
+    expect(results.map((entry) => entry.id)).toEqual(["auto", "meta-llama/llama-3.3-70b:free"]);
+    expect(results.map((entry) => entry.modelRef)).toEqual([
+      "openrouter/auto",
+      "openrouter/meta-llama/llama-3.3-70b:free",
+    ]);
+  });
 });
diff --git a/src/agents/model-scan.ts b/src/agents/model-scan.ts
index ba4775372..cb6e58f81 100644
--- a/src/agents/model-scan.ts
+++ b/src/agents/model-scan.ts
@@ -177,8 +177,13 @@ async function fetchOpenRouterModels(fetchImpl: typeof fetch): Promise<OpenRoute
     .map((entry) => {
       if (!entry || typeof entry !== "object") return null;
       const obj = entry as Record<string, unknown>;
-      const id = typeof obj.id === "string" ? obj.id.trim() : "";
+      let id = typeof obj.id === "string" ? obj.id.trim() : "";
       if (!id) return null;
+      // Normalize: strip "openrouter/" prefix if present to keep internal IDs clean.
+      // The prefix will be added back when constructing modelRef.
+      if (id.startsWith("openrouter/")) {
+        id = id.slice("openrouter/".length);
+      }
       const name = typeof obj.name === "string" && obj.name.trim() ? obj.name.trim() : id;
 
       const contextLength =
diff --git a/src/agents/pi-embedded-runner/model.ts b/src/agents/pi-embedded-runner/model.ts
index 15248aeaa..a6090f932 100644
--- a/src/agents/pi-embedded-runner/model.ts
+++ b/src/agents/pi-embedded-runner/model.ts
@@ -49,7 +49,14 @@ export function resolveModel(
   const resolvedAgentDir = agentDir ?? resolveClawdbotAgentDir();
   const authStorage = discoverAuthStorage(resolvedAgentDir);
   const modelRegistry = discoverModels(authStorage, resolvedAgentDir);
-  const model = modelRegistry.find(provider, modelId) as Model<Api> | null;
+  let model = modelRegistry.find(provider, modelId) as Model<Api> | null;
+
+  // Fallback: Some models in pi-ai have the provider prefix in their ID (e.g., "openrouter/auto").
+  // Our internal representation normalizes this to "auto", but pi-ai expects "openrouter/auto".
+  if (!model && provider === "openrouter") {
+    model = modelRegistry.find(provider, `${provider}/${modelId}`) as Model<Api> | null;
+  }
+
   if (!model) {
     const providers = cfg?.models?.providers ?? {};
     const inlineModels = buildInlineProviderModels(providers);