Build with Kestrel

The Build journey follows the shipped Reference agent from a first server-side request to streaming, memory, waiting, Next.js routes, and observability. You keep the same profile and session model throughout, so every step extends something already working.

Start building

1. Build your first agent and inspect its terminal result.
2. Stream the next request without changing session continuity.
3. Add explicit session memory.
4. Expose the agent through Next.js routes.
5. Handle waiting, resume, and cancellation.
6. Add observability before production operation.

Start with Build your first agent, then add only the integration capabilities your application needs.

Handle results correctly

Before shipping, read Protocol and results. A terminal result always contains assistantText: string | null; human-facing text is not inferred from structured finalized data. Use Runner events for the exact streaming vocabulary and Upgrading to 0.7 for compatibility changes.