Summary

copilotkit@2.0.0 (released ~3 days ago) rewrote the CopilotKit CLI and removed the --no-banner flag. create-ag-ui-app still passes that flag to the spawned npx copilotkit@latest create, which now aborts with Unknown option '--no-banner' whenever a user picks CopilotKit/Next.js. This PR drops the unsupported flag from the spawn argv.

Reproduction (from #1627)

$ npx create-ag-ui-app@latest

   █████╗  ██████╗       ██╗   ██╗ ██╗
  ...
  Agent User Interactivity Protocol

✔ What client do you want to use? CopilotKit/Next.js
✔ What would you like to name your project? my-ag-ui-app
(node:3653) [DEP0190] DeprecationWarning: Passing args to a child process with shell option true ...
Unknown option '--no-banner'

❌ Project creation failed.

Fix

   const copilotkit = spawn("npx",
     [
       "copilotkit@latest",
       "create",
-      "--no-banner",
       "-n", projectName.name,
       ...frameworkArgs,
     ],

sdks/typescript/packages/cli/src/index.ts, inside handleCopilotKitNextJs(). One-line removal.

Backward compatibility

The spawn target is hard-coded to copilotkit@latest, so users always resolve to the latest dist-tag.

• copilotkit ≥ 2.0.0 (current latest, what was broken): fixed.
• copilotkit 1.x: --no-banner was a cosmetic -q, --no-banner that suppressed the banner. Removing the flag means CopilotKit's banner now prints during nested creation — harmless. In practice this path is unreachable since @latest no longer resolves to 1.x.

No replacement flag exists in v2 (copilotkit create v2 only accepts -n -i -f -h).

Testing

• pnpm --filter create-ag-ui-app build — clean
• pnpm --filter create-ag-ui-app typecheck — clean
• pnpm --filter create-ag-ui-app test:exports (publint --strict + attw) — clean
• End-to-end smoke: ran the locally-built CLI with --mastra, scaffolding completed successfully against current copilotkit@latest (project smoke-test created, no Unknown option error).

Out of scope (separate follow-up)

Noticed while reading the file: line 113 reads options.crewiAiFlows while line 43 declares the flag as crewaiFlows (typo: crewi vs crewai). CrewAI Flows scaffolding via the framework flag is silently broken — happy to file a follow-up issue/PR after this one merges.

Fixes #1627