diff --git a/src/web/public/settings-ui.js b/src/web/public/settings-ui.js
index e8fed034..f967a3c8 100644
--- a/src/web/public/settings-ui.js
+++ b/src/web/public/settings-ui.js
@@ -3160,12 +3160,18 @@ Object.assign(CodemanApp.prototype, {
   /** Keep the launch surfaces in sync with Settings mutations without a reload. */
   _syncCliLaunchCatalog() {
     if (!Array.isArray(this._cliList) || this._cliList.length === 0) return;
+    // /api/clis rows carry no capabilities, so keep the served catalog's `external`
+    // (isExternalCliSession() reads it). A new custom CLI has none and falls back to `kind`.
+    const previous = new Map(
+      (Array.isArray(window.__codemanCliCatalog) ? window.__codemanCliCatalog : []).map((cli) => [cli.id, cli])
+    );
     window.__codemanCliCatalog = this._cliList.map((cli) => ({
       id: cli.id,
       label: cli.label,
       shortBadge: cli.shortBadge,
       order: cli.order,
       kind: cli.kind,
+      external: previous.get(cli.id)?.external,
       enabled: cli.enabled,
       available: cli.kind === 'shell' || (cli.enabled && cli.installed),
     }));
diff --git a/src/web/routes/cli-registry-routes.ts b/src/web/routes/cli-registry-routes.ts
index a4d4b136..3b75ffda 100644
--- a/src/web/routes/cli-registry-routes.ts
+++ b/src/web/routes/cli-registry-routes.ts
@@ -312,7 +312,9 @@ export function registerCliRegistryRoutes(app: FastifyInstance): void {
   // admin/settings surface; every SPAWN-time caller elsewhere uses
   // enabledClis() instead). Deliberately excludes launch/env/capabilities/
   // overlays/discovery — the same rule every other catalogue-export surface in
-  // this codebase follows.
+  // this codebase follows, with one deliberate exception: the page catalog
+  // (`window.__codemanCliCatalog`, server.ts) carries `capabilities.external`,
+  // which Session Options reads to keep Claude's Respawn and Ralph tabs.
   //
   // NOT gated on cliManagementEnabled: reading the list is cheap and is not
   // the risky part. The Settings UI section simply never fetches this while
diff --git a/test/run-mode-ui.test.ts b/test/run-mode-ui.test.ts
index d237b129..b6f82047 100644
--- a/test/run-mode-ui.test.ts
+++ b/test/run-mode-ui.test.ts
@@ -556,6 +556,25 @@ describe('Codex quick start settings', () => {
       expect(context.isExternalCliSession('custom-agent')).toBe(true);
     });
 
+    it('keeps the served external flag when App Settings resyncs the catalog from /api/clis', () => {
+      const catalog = CATALOG.map((cli) => ({ ...cli, external: cli.id !== 'claude' && cli.id !== 'shell' }));
+      const { app, context } = loadUi(undefined, catalog);
+      // /api/clis rows: no capabilities, so no `external`.
+      app._cliList = CATALOG.map((cli) => ({ ...cli, installed: true }));
+      app.runMode = 'claude';
+      app._syncCliLaunchCatalog();
+      expect(context.isExternalCliSession('claude')).toBe(false);
+      expect(context.isExternalCliSession('codex')).toBe(true);
+    });
+
+    it('gates Session Options on isExternalCliSession, not the launch-path check', () => {
+      const src = readFileSync(resolve(import.meta.dirname, '../src/web/public/session-ui.js'), 'utf8');
+      const open = src.slice(src.indexOf('\n  openSessionOptions('));
+      const body = open.slice(0, open.indexOf('\n  },'));
+      expect(body).toContain('isExternalCliSession(session.mode)');
+      expect(body).not.toContain('isExternalCliRunMode(');
+    });
+
     it('shows everything when the flags were never injected', () => {
       // A cached page from a build without the injection, or a solo popup. Hiding
       // every run button on a doubt would leave a working install nothing to click.