Building durable Agents with Workflow DevKit & AI SDK - Peter Wielander, Vercel

Eliminating production boilerplate

The workflow pattern removes the need to manually wire up queues, databases, and error handling for long-running agents by providing a deterministic orchestration layer that persists state and retries failed steps automatically.

Deterministic step isolation

The `use workflow` directive compiles agent loops into isolated bundles that separate LLM calls and tool executions into discrete, replayable steps with cached inputs and outputs.

Serverless durability

Each marked step runs in an isolated serverless instance, allowing agents to execute for hours or days across multiple invocations without losing context or state.

Minimal code changes required

Migrate existing AI SDK agents by simply adding the `use workflow` directive to the orchestration function and wrapping tool executions with `use step`, or use the pre-built `DurableAgent` class to handle LLM calls automatically.

Framework integration

The kit provides Next.js helpers (`withWorkflow`) and TypeScript compiler plugins that maintain deterministic execution while preserving compatibility with existing frontends and any cloud provider.

Stream persistence

The `getWritable` API creates durable streams that exist independently of the API handler lifecycle, allowing tools to write data packets that persist even if the client disconnects.

Built-in local debugging

Running `npx workflow web` launches a local observability UI that visualizes every workflow run, step execution, input/output data, and associated events without additional instrumentation.

Resumable client sessions

Streams remain active on the backend even after client disconnections, enabling users to reconnect and resume exactly where the agent left off, critical for long-running coding or research tasks.

Human-in-the-loop support

The framework supports suspending workflows at any step to await human approval via webhooks or manual resume commands, making it easy to implement safety checks for production agents.