diff --git a/src/commands/auth-choice.test.ts b/src/commands/auth-choice.test.ts
index 4cf6c8dc3..c22868ea7 100644
--- a/src/commands/auth-choice.test.ts
+++ b/src/commands/auth-choice.test.ts
@@ -150,4 +150,75 @@ describe("applyAuthChoice", () => {
     expect(result.config.models?.providers?.["opencode-zen"]).toBeUndefined();
     expect(result.agentModelOverride).toBe("opencode/claude-opus-4-5");
   });
+
+  it("uses existing OPENROUTER_API_KEY when selecting openrouter-api-key", async () => {
+    tempStateDir = await fs.mkdtemp(path.join(os.tmpdir(), "clawdbot-auth-"));
+    process.env.CLAWDBOT_STATE_DIR = tempStateDir;
+    process.env.CLAWDBOT_AGENT_DIR = path.join(tempStateDir, "agent");
+    process.env.PI_CODING_AGENT_DIR = process.env.CLAWDBOT_AGENT_DIR;
+    process.env.OPENROUTER_API_KEY = "sk-openrouter-test";
+
+    const text = vi.fn();
+    const select: WizardPrompter["select"] = vi.fn(
+      async (params) => params.options[0]?.value as never,
+    );
+    const multiselect: WizardPrompter["multiselect"] = vi.fn(async () => []);
+    const confirm = vi.fn(async () => true);
+    const prompter: WizardPrompter = {
+      intro: vi.fn(noopAsync),
+      outro: vi.fn(noopAsync),
+      note: vi.fn(noopAsync),
+      select,
+      multiselect,
+      text,
+      confirm,
+      progress: vi.fn(() => ({ update: noop, stop: noop })),
+    };
+    const runtime: RuntimeEnv = {
+      log: vi.fn(),
+      error: vi.fn(),
+      exit: vi.fn((code: number) => {
+        throw new Error(`exit:${code}`);
+      }),
+    };
+
+    const result = await applyAuthChoice({
+      authChoice: "openrouter-api-key",
+      config: {},
+      prompter,
+      runtime,
+      setDefaultModel: true,
+    });
+
+    expect(confirm).toHaveBeenCalledWith(
+      expect.objectContaining({
+        message: expect.stringContaining("OPENROUTER_API_KEY"),
+      }),
+    );
+    expect(text).not.toHaveBeenCalled();
+    expect(result.config.auth?.profiles?.["openrouter:default"]).toMatchObject({
+      provider: "openrouter",
+      mode: "api_key",
+    });
+    expect(result.config.agents?.defaults?.model?.primary).toBe(
+      "openrouter/auto",
+    );
+
+    const authProfilePath = path.join(
+      tempStateDir,
+      "agents",
+      "main",
+      "agent",
+      "auth-profiles.json",
+    );
+    const raw = await fs.readFile(authProfilePath, "utf8");
+    const parsed = JSON.parse(raw) as {
+      profiles?: Record<string, { key?: string }>;
+    };
+    expect(parsed.profiles?.["openrouter:default"]?.key).toBe(
+      "sk-openrouter-test",
+    );
+
+    delete process.env.OPENROUTER_API_KEY;
+  });
 });
diff --git a/src/commands/auth-choice.ts b/src/commands/auth-choice.ts
index 08eeaa997..729616de9 100644
--- a/src/commands/auth-choice.ts
+++ b/src/commands/auth-choice.ts
@@ -9,6 +9,7 @@ import {
   CODEX_CLI_PROFILE_ID,
   ensureAuthProfileStore,
   listProfilesForProvider,
+  resolveAuthProfileOrder,
   upsertAuthProfile,
 } from "../agents/auth-profiles.js";
 import { DEFAULT_MODEL, DEFAULT_PROVIDER } from "../agents/defaults.js";
@@ -371,16 +372,65 @@ export async function applyAuthChoice(params: {
       "OpenAI API key",
     );
   } else if (params.authChoice === "openrouter-api-key") {
-    const key = await params.prompter.text({
-      message: "Enter OpenRouter API key",
-      validate: (value) => (value?.trim() ? undefined : "Required"),
+    const store = ensureAuthProfileStore(params.agentDir, {
+      allowKeychainPrompt: false,
     });
-    await setOpenrouterApiKey(String(key).trim(), params.agentDir);
-    nextConfig = applyAuthProfileConfig(nextConfig, {
-      profileId: "openrouter:default",
+    const profileOrder = resolveAuthProfileOrder({
+      cfg: nextConfig,
+      store,
       provider: "openrouter",
-      mode: "api_key",
     });
+    const existingProfileId = profileOrder.find((profileId) =>
+      Boolean(store.profiles[profileId]),
+    );
+    const existingCred = existingProfileId
+      ? store.profiles[existingProfileId]
+      : undefined;
+    let profileId = "openrouter:default";
+    let mode: "api_key" | "oauth" | "token" = "api_key";
+    let hasCredential = false;
+
+    if (existingProfileId && existingCred?.type) {
+      profileId = existingProfileId;
+      mode =
+        existingCred.type === "oauth"
+          ? "oauth"
+          : existingCred.type === "token"
+            ? "token"
+            : "api_key";
+      hasCredential = true;
+    }
+
+    if (!hasCredential) {
+      const envKey = resolveEnvApiKey("openrouter");
+      if (envKey) {
+        const useExisting = await params.prompter.confirm({
+          message: `Use existing OPENROUTER_API_KEY (${envKey.source})?`,
+          initialValue: true,
+        });
+        if (useExisting) {
+          await setOpenrouterApiKey(envKey.apiKey, params.agentDir);
+          hasCredential = true;
+        }
+      }
+    }
+
+    if (!hasCredential) {
+      const key = await params.prompter.text({
+        message: "Enter OpenRouter API key",
+        validate: (value) => (value?.trim() ? undefined : "Required"),
+      });
+      await setOpenrouterApiKey(String(key).trim(), params.agentDir);
+      hasCredential = true;
+    }
+
+    if (hasCredential) {
+      nextConfig = applyAuthProfileConfig(nextConfig, {
+        profileId,
+        provider: "openrouter",
+        mode,
+      });
+    }
     if (params.setDefaultModel) {
       nextConfig = applyOpenrouterConfig(nextConfig);
       await params.prompter.note(
diff --git a/src/commands/onboard-auth.test.ts b/src/commands/onboard-auth.test.ts
index 8791ed0e0..7be366218 100644
--- a/src/commands/onboard-auth.test.ts
+++ b/src/commands/onboard-auth.test.ts
@@ -9,8 +9,11 @@ import {
   applyAuthProfileConfig,
   applyMinimaxApiConfig,
   applyMinimaxApiProviderConfig,
+  applyOpenrouterConfig,
+  applyOpenrouterProviderConfig,
   applyOpencodeZenConfig,
   applyOpencodeZenProviderConfig,
+  OPENROUTER_DEFAULT_MODEL_REF,
   writeOAuthCredentials,
 } from "./onboard-auth.js";
 
@@ -301,3 +304,48 @@ describe("applyOpencodeZenConfig", () => {
     ]);
   });
 });
+
+describe("applyOpenrouterProviderConfig", () => {
+  it("adds allowlist entry for the default model", () => {
+    const cfg = applyOpenrouterProviderConfig({});
+    const models = cfg.agents?.defaults?.models ?? {};
+    expect(Object.keys(models)).toContain(OPENROUTER_DEFAULT_MODEL_REF);
+  });
+
+  it("preserves existing alias for the default model", () => {
+    const cfg = applyOpenrouterProviderConfig({
+      agents: {
+        defaults: {
+          models: {
+            [OPENROUTER_DEFAULT_MODEL_REF]: { alias: "Router" },
+          },
+        },
+      },
+    });
+    expect(
+      cfg.agents?.defaults?.models?.[OPENROUTER_DEFAULT_MODEL_REF]?.alias,
+    ).toBe("Router");
+  });
+});
+
+describe("applyOpenrouterConfig", () => {
+  it("sets correct primary model", () => {
+    const cfg = applyOpenrouterConfig({});
+    expect(cfg.agents?.defaults?.model?.primary).toBe(
+      OPENROUTER_DEFAULT_MODEL_REF,
+    );
+  });
+
+  it("preserves existing model fallbacks", () => {
+    const cfg = applyOpenrouterConfig({
+      agents: {
+        defaults: {
+          model: { fallbacks: ["anthropic/claude-opus-4-5"] },
+        },
+      },
+    });
+    expect(cfg.agents?.defaults?.model?.fallbacks).toEqual([
+      "anthropic/claude-opus-4-5",
+    ]);
+  });
+});