diff --git a/src/commands/auth/setup.test.ts b/src/commands/auth/setup.test.ts
index fb16593..85b03fc 100644
--- a/src/commands/auth/setup.test.ts
+++ b/src/commands/auth/setup.test.ts
@@ -116,6 +116,28 @@ describe('runSetup', () => {
     expect(readAuth()?.tokens.accessToken).toBe('old-at'); // creds untouched
   });
 
+  it('signs into the current target when the stored credential is for a different env', async () => {
+    // Credential is for dev; this run targets production - do not introspect cross-env, sign in fresh.
+    saveAuth(existingAuth);
+    process.env['AGENTAGE_SITE_FQDN'] = 'agentage.io';
+    const { deps } = makeDeps();
+    await runSetup({}, deps);
+    expect(deps.introspect).not.toHaveBeenCalled();
+    expect(deps.register).toHaveBeenCalled();
+    expect(readAuth()?.siteFqdn).toBe('agentage.io');
+    expect(readAuth()?.clientId).toBe('client-1');
+  });
+
+  it('signs into dev when a production credential meets a dev target', async () => {
+    saveAuth({ ...existingAuth, siteFqdn: 'agentage.io' });
+    process.env['AGENTAGE_SITE_FQDN'] = 'dev.agentage.io';
+    const { deps } = makeDeps();
+    await runSetup({}, deps);
+    expect(deps.introspect).not.toHaveBeenCalled();
+    expect(deps.register).toHaveBeenCalled();
+    expect(readAuth()?.siteFqdn).toBe('dev.agentage.io');
+  });
+
   it('auto-enters sign-in when the stored session is terminally expired', async () => {
     saveAuth(existingAuth);
     const { deps } = makeDeps();
diff --git a/src/commands/auth/setup.ts b/src/commands/auth/setup.ts
index 3b6c43a..4ce7f10 100644
--- a/src/commands/auth/setup.ts
+++ b/src/commands/auth/setup.ts
@@ -11,6 +11,7 @@ import {
   type AuthState,
 } from '../../lib/fs/config.js';
 import { AuthRequiredError, introspectToken } from '../../lib/auth/api.js';
+import { detectEnvMismatch } from '../../lib/auth/env-match.js';
 import {
   buildAuthorizeUrl,
   exchangeCode,
@@ -90,8 +91,17 @@ const disconnect = async (deps: SetupDeps): Promise<void> => {
 };
 
 // Validate the stored session instead of trusting mere token presence. Returns true to short-circuit
-// (valid or a transient blip - creds intact), false to proceed into a fresh sign-in (truly expired).
+// (valid or a transient blip - creds intact), false to proceed into a fresh sign-in (truly expired or
+// the credential belongs to a different target than the current run).
 const alreadySignedIn = async (auth: AuthState, deps: SetupDeps): Promise<boolean> => {
+  const mismatch = detectEnvMismatch(auth, siteFqdn());
+  if (mismatch) {
+    console.log(
+      `Signed in to ${mismatch.credentialFqdn} (${mismatch.credentialEnv}), but this run targets ` +
+        `${mismatch.targetFqdn} (${mismatch.targetEnv}) - signing you into ${mismatch.targetEnv}.\n`
+    );
+    return false; // proceed to a fresh sign-in against the current target
+  }
   try {
     await deps.introspect(auth, links(auth.siteFqdn));
     console.log(
diff --git a/src/commands/status/status.test.ts b/src/commands/status/status.test.ts
index cd57754..8587bec 100644
--- a/src/commands/status/status.test.ts
+++ b/src/commands/status/status.test.ts
@@ -70,6 +70,27 @@ describe('printStatus', () => {
     expect(out).toContain('signed in (session active)');
   });
 
+  it('renders a neutral env-mismatch line naming both sides, never expired', () => {
+    const out = captureLines({
+      ...baseReport,
+      auth: {
+        signedIn: false,
+        mismatch: {
+          credentialFqdn: 'dev.agentage.io',
+          credentialEnv: 'development',
+          targetFqdn: 'agentage.io',
+          targetEnv: 'production',
+        },
+        note: 'signed in to dev.agentage.io - CLI targets agentage.io (production)',
+      },
+    });
+    expect(out).toContain('signed in to dev.agentage.io');
+    expect(out).toContain('CLI targets agentage.io (production)');
+    expect(out).not.toContain('session expired');
+    expect(out).not.toContain('✗');
+    expect(out).toContain('!');
+  });
+
   it('prints the setup hint when signed out', () => {
     const out = captureLines({
       ...baseReport,
diff --git a/src/commands/status/status.ts b/src/commands/status/status.ts
index c096439..1b149b6 100644
--- a/src/commands/status/status.ts
+++ b/src/commands/status/status.ts
@@ -21,6 +21,9 @@ const row = (label: string, value: string): void => {
 // access-token expiry, which misreads as "yesterday" near midnight in positive-UTC zones.
 // Introspection already proved the session is active server-side.
 const authLine = (auth: StatusReport['auth']): string => {
+  // Env mismatch: the credential is valid but for another target - neutral `!`, not the expired ✗.
+  if (auth.mismatch)
+    return `${chalk.yellow('!')} ${auth.note ?? 'signed in to another environment'}`;
   if (!auth.signedIn) return `${mark(false)} ${auth.note ?? 'not signed in'}`;
   // Transient: we hold a valid-looking token but could not re-verify - a non-terminal `~`, never ✗.
   if (auth.transient) return `${chalk.yellow('~')} ${auth.note ?? 'signed in'}`;
diff --git a/src/lib/auth/env-match.test.ts b/src/lib/auth/env-match.test.ts
new file mode 100644
index 0000000..55e591b
--- /dev/null
+++ b/src/lib/auth/env-match.test.ts
@@ -0,0 +1,44 @@
+import { describe, expect, it } from 'vitest';
+import { type AuthState } from '../fs/config.js';
+import { detectEnvMismatch } from './env-match.js';
+
+const authFor = (siteFqdn: string): AuthState => ({
+  siteFqdn,
+  clientId: 'c1',
+  tokens: { accessToken: 'at' },
+});
+
+describe('detectEnvMismatch', () => {
+  it('returns null when the credential fqdn matches the target', () => {
+    expect(detectEnvMismatch(authFor('dev.agentage.io'), 'dev.agentage.io')).toBeNull();
+    expect(detectEnvMismatch(authFor('agentage.io'), 'agentage.io')).toBeNull();
+  });
+
+  it('flags a dev credential against a production target', () => {
+    expect(detectEnvMismatch(authFor('dev.agentage.io'), 'agentage.io')).toEqual({
+      credentialFqdn: 'dev.agentage.io',
+      credentialEnv: 'development',
+      targetFqdn: 'agentage.io',
+      targetEnv: 'production',
+    });
+  });
+
+  it('flags a production credential against a dev target', () => {
+    expect(detectEnvMismatch(authFor('agentage.io'), 'dev.agentage.io')).toEqual({
+      credentialFqdn: 'agentage.io',
+      credentialEnv: 'production',
+      targetFqdn: 'dev.agentage.io',
+      targetEnv: 'development',
+    });
+  });
+
+  it('classifies a localhost target as development', () => {
+    const m = detectEnvMismatch(authFor('agentage.io'), 'localhost:3000');
+    expect(m?.targetEnv).toBe('development');
+    expect(m?.credentialEnv).toBe('production');
+  });
+
+  it('normalizes scheme and trailing slash before comparing', () => {
+    expect(detectEnvMismatch(authFor('https://agentage.io/'), 'agentage.io')).toBeNull();
+  });
+});
diff --git a/src/lib/auth/env-match.ts b/src/lib/auth/env-match.ts
new file mode 100644
index 0000000..30d52b4
--- /dev/null
+++ b/src/lib/auth/env-match.ts
@@ -0,0 +1,25 @@
+import { type AuthState } from '../fs/config.js';
+import { environment, normalizeFqdn, type Env } from '../net/origins.js';
+
+export interface AuthEnvMismatch {
+  credentialFqdn: string;
+  credentialEnv: Env;
+  targetFqdn: string;
+  targetEnv: Env;
+}
+
+// The stored credential belongs to the environment it was issued for (auth.siteFqdn); the CLI's
+// current target comes from AGENTAGE_SITE_FQDN (production default). Introspecting a dev credential
+// against production rejects it and misreads as "expired" - so detect the mismatch by normalized
+// fqdn BEFORE any introspection. Returns null when the credential matches the current target.
+export const detectEnvMismatch = (auth: AuthState, targetFqdn: string): AuthEnvMismatch | null => {
+  const credentialFqdn = normalizeFqdn(auth.siteFqdn);
+  const target = normalizeFqdn(targetFqdn);
+  if (credentialFqdn === target) return null;
+  return {
+    credentialFqdn,
+    credentialEnv: environment(credentialFqdn),
+    targetFqdn: target,
+    targetEnv: environment(target),
+  };
+};
diff --git a/src/lib/status/status-info.test.ts b/src/lib/status/status-info.test.ts
index 471d58e..ff36ea7 100644
--- a/src/lib/status/status-info.test.ts
+++ b/src/lib/status/status-info.test.ts
@@ -173,6 +173,30 @@ describe('gatherStatus', () => {
     expect(report.auth.note).not.toContain('expired');
   });
 
+  it('reports an env mismatch (dev credential, prod target) instead of session expired', async () => {
+    // No fetch stub for get-session: a mismatch must never introspect cross-environment.
+    const report = await gatherStatus(auth, 'agentage.io');
+    expect(report.auth.signedIn).toBe(false);
+    expect(report.auth.mismatch).toEqual({
+      credentialFqdn: 'dev.agentage.io',
+      credentialEnv: 'development',
+      targetFqdn: 'agentage.io',
+      targetEnv: 'production',
+    });
+    expect(report.auth.note).toContain('dev.agentage.io');
+    expect(report.auth.note).toContain('agentage.io');
+    expect(report.auth.note).not.toContain('session expired');
+  });
+
+  it('reports an env mismatch in the reverse direction (prod credential, dev target)', async () => {
+    const prodAuth = { ...auth, siteFqdn: 'agentage.io' };
+    const report = await gatherStatus(prodAuth, 'dev.agentage.io');
+    expect(report.auth.signedIn).toBe(false);
+    expect(report.auth.mismatch?.credentialEnv).toBe('production');
+    expect(report.auth.mismatch?.targetEnv).toBe('development');
+    expect(report.auth.note).not.toContain('session expired');
+  });
+
   it('reports the daemon as stopped when no pidfile is present', async () => {
     vi.stubGlobal(
       'fetch',
diff --git a/src/lib/status/status-info.ts b/src/lib/status/status-info.ts
index b0ee55c..236a146 100644
--- a/src/lib/status/status-info.ts
+++ b/src/lib/status/status-info.ts
@@ -1,4 +1,5 @@
 import { AuthRequiredError, introspectToken } from '../auth/api.js';
+import { detectEnvMismatch, type AuthEnvMismatch } from '../auth/env-match.js';
 import { type AuthState } from '../fs/config.js';
 import { health, syncStatus } from '../daemon/daemon-client.js';
 import { fetchJsonUnref } from '../net/http.js';
@@ -33,7 +34,15 @@ export interface StatusReport {
   fqdn: string;
   env: Env;
   target: { fqdn: string; env: Env; reachable: boolean };
-  auth: { signedIn: boolean; tokenExpiresAt?: string; note?: string; transient?: boolean };
+  auth: {
+    signedIn: boolean;
+    tokenExpiresAt?: string;
+    note?: string;
+    transient?: boolean;
+    // Set when the stored credential's env differs from the current target: signedIn is false and the
+    // printer renders a neutral "signed in to X - CLI targets Y" line, never "session expired".
+    mismatch?: AuthEnvMismatch;
+  };
   endpoint: { url: string; reachable: boolean };
   update: UpdateInfo;
   daemon?: DaemonStatus;
@@ -108,6 +117,16 @@ const classifyAuthError = (err: unknown): StatusReport['auth'] =>
     ? { signedIn: false, note: 'session expired - run: agentage setup' }
     : { signedIn: true, transient: true, note: 'signed in (could not re-verify - temporary)' };
 
+// A credential issued for one environment, checked against another, is not expired - it belongs
+// elsewhere. Name both sides and hint the two fixes, without introspecting cross-environment.
+const mismatchAuth = (m: AuthEnvMismatch): StatusReport['auth'] => ({
+  signedIn: false,
+  mismatch: m,
+  note:
+    `signed in to ${m.credentialFqdn} - CLI targets ${m.targetFqdn} (${m.targetEnv}); ` +
+    `run: agentage setup to sign into ${m.targetEnv}, or set AGENTAGE_SITE_FQDN=${m.credentialFqdn}`,
+});
+
 export const gatherStatus = async (auth: AuthState | null, fqdn: string): Promise<StatusReport> => {
   const target = links(fqdn);
   const env = environment(fqdn);
@@ -133,6 +152,11 @@ export const gatherStatus = async (auth: AuthState | null, fqdn: string): Promis
     vaults: buildVaultStatuses(probe.sync, probe.status.running),
   };
   if (!auth) return report;
+  const mismatch = detectEnvMismatch(auth, fqdn);
+  if (mismatch) {
+    report.auth = mismatchAuth(mismatch);
+    return report;
+  }
   try {
     const session = await introspectToken(auth, target);
     report.auth = { signedIn: true, tokenExpiresAt: session.expiresAt };