diff --git a/src/auto-reply/reply/agent-runner.authprofileid-fallback.test.ts b/src/auto-reply/reply/agent-runner.authprofileid-fallback.test.ts
new file mode 100644
index 000000000..419da8d4d
--- /dev/null
+++ b/src/auto-reply/reply/agent-runner.authprofileid-fallback.test.ts
@@ -0,0 +1,149 @@
+import { describe, expect, it, vi } from "vitest";
+import type { TemplateContext } from "../templating.js";
+import type { FollowupRun, QueueSettings } from "./queue.js";
+import { createMockTypingController } from "./test-helpers.js";
+
+const runEmbeddedPiAgentMock = vi.fn();
+
+vi.mock("../../agents/model-fallback.js", () => ({
+  runWithModelFallback: async ({
+    run,
+  }: {
+    run: (provider: string, model: string) => Promise<unknown>;
+  }) => ({
+    // Force a cross-provider fallback candidate
+    result: await run("openai-codex", "gpt-5.2"),
+    provider: "openai-codex",
+    model: "gpt-5.2",
+  }),
+}));
+
+vi.mock("../../agents/pi-embedded.js", () => ({
+  queueEmbeddedPiMessage: vi.fn().mockReturnValue(false),
+  runEmbeddedPiAgent: (params: unknown) => runEmbeddedPiAgentMock(params),
+}));
+
+vi.mock("./queue.js", async () => {
+  const actual = await vi.importActual<typeof import("./queue.js")>("./queue.js");
+  return {
+    ...actual,
+    enqueueFollowupRun: vi.fn(),
+    scheduleFollowupDrain: vi.fn(),
+  };
+});
+
+import { runReplyAgent } from "./agent-runner.js";
+
+function createBaseRun(params: { runOverrides?: Partial<FollowupRun["run"]> }) {
+  const typing = createMockTypingController();
+  const sessionCtx = {
+    Provider: "telegram",
+    OriginatingTo: "chat",
+    AccountId: "primary",
+    MessageSid: "msg",
+    Surface: "telegram",
+  } as unknown as TemplateContext;
+
+  const resolvedQueue = { mode: "interrupt" } as unknown as QueueSettings;
+
+  const followupRun = {
+    prompt: "hello",
+    summaryLine: "hello",
+    enqueuedAt: Date.now(),
+    run: {
+      agentId: "main",
+      agentDir: "/tmp/agent",
+      sessionId: "session",
+      sessionKey: "main",
+      messageProvider: "telegram",
+      sessionFile: "/tmp/session.jsonl",
+      workspaceDir: "/tmp",
+      config: {},
+      skillsSnapshot: {},
+      provider: "anthropic",
+      model: "claude-opus",
+      authProfileId: "anthropic:clawd",
+      authProfileIdSource: "manual",
+      thinkLevel: "low",
+      verboseLevel: "off",
+      elevatedLevel: "off",
+      bashElevated: {
+        enabled: false,
+        allowed: false,
+        defaultLevel: "off",
+      },
+      timeoutMs: 5_000,
+      blockReplyBreak: "message_end",
+    },
+  } as unknown as FollowupRun;
+
+  return {
+    typing,
+    sessionCtx,
+    resolvedQueue,
+    followupRun: {
+      ...followupRun,
+      run: { ...followupRun.run, ...params.runOverrides },
+    },
+  };
+}
+
+describe("authProfileId fallback scoping", () => {
+  it("drops authProfileId when provider changes during fallback", async () => {
+    runEmbeddedPiAgentMock.mockReset();
+    runEmbeddedPiAgentMock.mockResolvedValue({ payloads: [{ text: "ok" }], meta: {} });
+
+    const sessionKey = "main";
+    const sessionEntry = {
+      sessionId: "session",
+      updatedAt: Date.now(),
+      totalTokens: 1,
+      compactionCount: 0,
+    };
+
+    const { typing, sessionCtx, resolvedQueue, followupRun } = createBaseRun({
+      runOverrides: {
+        provider: "anthropic",
+        model: "claude-opus",
+        authProfileId: "anthropic:clawd",
+        authProfileIdSource: "manual",
+      },
+    });
+
+    await runReplyAgent({
+      commandBody: "hello",
+      followupRun,
+      queueKey: sessionKey,
+      resolvedQueue,
+      shouldSteer: false,
+      shouldFollowup: false,
+      isActive: false,
+      isStreaming: false,
+      typing,
+      sessionCtx,
+      sessionEntry,
+      sessionStore: { [sessionKey]: sessionEntry },
+      sessionKey,
+      storePath: undefined,
+      defaultModel: "anthropic/claude-opus-4-5",
+      agentCfgContextTokens: 100_000,
+      resolvedVerboseLevel: "off",
+      isNewSession: false,
+      blockStreamingEnabled: false,
+      resolvedBlockStreamingBreak: "message_end",
+      shouldInjectGroupIntro: false,
+      typingMode: "instant",
+    });
+
+    expect(runEmbeddedPiAgentMock).toHaveBeenCalledTimes(1);
+    const call = runEmbeddedPiAgentMock.mock.calls[0]?.[0] as {
+      authProfileId?: unknown;
+      authProfileIdSource?: unknown;
+      provider?: unknown;
+    };
+
+    expect(call.provider).toBe("openai-codex");
+    expect(call.authProfileId).toBeUndefined();
+    expect(call.authProfileIdSource).toBeUndefined();
+  });
+});