> ## Documentation Index > Fetch the complete documentation index at: https://docs.rebuno.io/llms.txt > Use this file to discover all available pages before exploring further. # TypeScript SDK Build agents and clients for Rebuno. The SDK is ESM-only, has no runtime dependencies, and needs Node 22 or later. See the [Quickstart](/sdk/typescript/getting-started) to install and run it. ## What you write You write one ordinary async function. Rebuno runs that handler for you. Route every non-deterministic effect through the kernel, which records the outcome. Three ways to do it: Records a `tool_call` step: actions the agent takes, such as a search, an email, or a database write. Records an `llm_call` step: calls to an LLM provider. Records a `local` step: local non-determinism such as the clock, a random choice, or a fresh id. On a re-dispatch the handler runs again from the top. Any step with a recorded result replays it instead of running a second time. ## Sections Install, configure, and run a complete example. The `Agent` host, input validation, `serve` vs `fetch`, and lifecycle. `defineTool`, `wrapTool`, idempotency, blocking work, and MCP tools. `rebunoFetch` and `createRebunoFetch`. `step()` for durable local work. Creating and inspecting executions, and approvals. The error class hierarchy. Step identity, replay, heartbeats, and the kernel protocol.