/migrating-to-workflow-sdk

name: migrating-to-workflow-sdk
description: Migrates Temporal, Inngest, Trigger.dev, and AWS Step Functions workflows to the Workflow SDK. Use when porting Activities, Workers, Signals, step.run(), step.waitForEvent(), Trigger.dev tasks / wait.forToken / triggerAndWait, ASL JSON state machines, Task/Choice/Wait/Parallel states, task tokens, or child workflows.
metadata:
  author: Vercel Inc.
  version: '0.2.0'

Migrating to the Workflow SDK

Use this skill when converting an existing orchestration system to the Workflow SDK.

Intake

1. Identify the source system:

• Temporal
• Inngest
• Trigger.dev
• AWS Step Functions

2. Identify the target runtime:

• Managed hosting -> keep examples focused on `start()`, `getRun()`, hooks/webhooks, and route handlers.
• Self-hosted -> also read `references/runtime-targets.md` and explicitly say the workflow/step code can stay the same, but deployment still needs a `World` implementation and startup bootstrap.

3. Extract the source constructs:

• entrypoint
• waits / timers
• external callbacks / approvals
• retries / failure handling
• child workflows / fan-out
• progress streaming
• external side effects

Default migration rules

• Put orchestration in `"use workflow"` functions.
• Put side effects, SDK calls, DB calls, HTTP calls, and stream I/O in `"use step"` functions.
• Use `sleep()` only in workflow context.
• For Signals, `step.waitForEvent()`, and `.waitForTaskToken`, choose exactly one resume surface:
• `resume/internal` -> `createHook()` + `resumeHook()` when the app resumes from server-side code with a deterministic business token.
• `resume/url/default` -> `createWebhook()` when the external system needs a generated callback URL and the default `202 Accepted` response is fine.
• `resume/url/manual` -> `createWebhook({ respondWith: 'manual' })` only when the prompt explicitly requires a custom response body, status, or headers.
• If a callback-URL prompt does not specify response semantics, default to `resume/url/default` and make the assumption explicit in `## Open Questions`.
• Never pair `createWebhook()` with `resumeHook()`, and never pass `token:` to `createWebhook()`.
• Wrap `start()` and `getRun()` inside `"use step"` functions for child runs.
• Use `getStepMetadata().stepId` as the idempotency key for external writes.
• Use `getWritable()` in workflow context to obtain the stream, but interact with it (write, close) only inside `"use step"` functions.
• Prefer rollback stacks for multi-step compensation.
• Choose app-boundary syntax in this order:

1. If the prompt explicitly asks for framework-agnostic app-boundary code, use plain `Request` / `Response` even when a framework like Hono is named. 2. Otherwise, if the target framework is named, shape app-boundary examples to that framework. 3. Otherwise, keep examples framework-agnostic with `Request` / `Response`. Do not default to Next.js-only route signatures unless Next.js is explicitly named.

> Fast memory aid: > - Callback URL + default ack -> `createWebhook()` > - Callback URL + custom ack -> `createWebhook({ respondWith: 'manual' })` > - Deterministic server-side resume -> `createHook()` + `resumeHook()`

Fast-path router

Load `references/resume-routing.md` when the source pauses for Signals, `step.waitForEvent()`, or `.waitForTaskToken`.

Fast defaults:

• callback URL only -> `resume/url/default`
• callback URL + explicit custom response -> `resume/url/manual`
• deterministic server-side resume -> `resume/internal`
• self-hosted -> add `runtime/self-hosted`
• named framework -> add `boundary/named-framework`
• explicit framework-agnostic request -> add `boundary/framework-agnostic`

Before drafting `## Migrated Code`, write the selected route keys in `## Migration Plan`.

Source references

• Temporal -> `references/temporal.md`
• Inngest -> `references/inngest.md`
• Trigger.dev -> `references/trigger-dev.md`
• AWS Step Functions -> `references/aws-step-functions.md`

Shared references

• `references/shared-patterns.md` — reusable code templates for hooks, child workflows, idempotency, streaming, and rollback.
• `references/runtime-targets.md` — Managed vs custom `World` guidance.
• `references/resume-routing.md` — route-key selection, obligations, and exact `## Migration Plan` shape.
• `references/retries.md` — canonical retry mechanics: `stepFn.maxRetries`, `RetryableError({ retryAfter })`, `FatalError`.

Required output shape

Return the migration in this structure:

## Migration Plan
## Source -> Target Mapping
## Migrated Code
## App Boundary / Resume Endpoints
## Verification Checklist
## Open Questions

Verification checklist

Fail the draft if any of these are true:

• [ ] `## Migration Plan` omits `Route keys`
• [ ] `## Migration Plan` omits `Why these route keys`
• [ ] `## Migration Plan` lists route keys that do not match the prompt
• [ ] `## Migration Plan` lists required code obligations that do not match the selected route keys
• [ ] Source-framework primitives remain in the migrated code
• [ ] Side effects remain in workflow context
• [ ] `sleep()` appears inside a step
• [ ] Stream interaction (`getWriter()`, `write()`, `close()`) appears inside a workflow function
• [ ] Child workflows call `start()` / `getRun()` directly from workflow context
• [ ] External writes omit idempotency keys
• [ ] Hooks/webhooks are missing where the source used signals, waitForEvent, or task tokens
• [ ] A callback-URL flow uses `createHook()` + `resumeHook()` instead of `createWebhook()`
• [ ] A `resume/url/default` or `resume/url/manual` migration invents a user-authored callback route or `resumeWebhook()` wrapper when `webhook.url` should be the only resume surface
• [ ] `createWebhook()` is given a custom `token` or paired with `resumeHook()`

Validation note:

• Reading webhook request data in workflow context is allowed. Only `request.respondWith()` is step-only.

Additional fail