The real thing: DeepSeek V4 + the bash tool suite + stdio chat + JSONL persistence, wired from `cordis.yml`. Where echo-agent proves the skeleton with mocks, this is a usable coding assistant.
Run with: `pnpm run demo:coding` (needs `DEEPSEEK_API_KEY` in the environment or a gitignored repo-root `.env`). See [coding-agent/README.md](coding-agent/README.md) for details.