implement event-sourced architecture

[pranaygp]

Pranay:

corresponding workflow-server PR: https://github.com/vercel/workflow-server/pull/154

important: This is a big change to the way workflows work since everything is now event sourced, I introduced new events types, and changed the shape of the step object (lastKnownError -> error and startedAt -> firstStartedAt). New event logs that use this published version of workflow will be incompatible with previous workflow version event logs. This doesn't affect the runtime of workflows since those are deployment pegged - but this does affect observability since the event shape looks different and the world spec has changed. The web-shared package just needs to be compatible with viewing workflow runs of the old schema for this to work correctly (which I believe it does, but please double check @VaguelySerious if I missed anything).

The currently failing e2e tests on vercel world are related to the CLI I believe (slack x-ref). However once we merged the workflow-server PR, we can drop the env var changes on the vercel deployments for PR so that this PR points to the main prod deployment, again and then I'll re-run e2e tests to make sure they work :)

I Also added a new docs page with diagrams to explain the event sourcing and state machine lifecycles (preview link):

small: I also removed the unused run paused/resumed stuff which we've never used to simplify

Summary

Implement event-sourced architecture for runs, steps, and hooks:

• Add run lifecycle events (run_created, run_started, run_completed, run_failed, run_cancelled)
• Add step_retrying event for non-fatal step failures that will be retried
• Remove fatal field from step_failed event (step_failed now implies terminal failure)
• Rename step's lastKnownError to error for consistency with server
• Update world-local, world-postgres, and world-vercel to create/update entities from events via events.create()
• Entities (runs, steps, hooks) are now materializations of the event log
• Fix hook token conflict error to use WorkflowAPIError with status 409
• Move event log corruption check to step_created event for earlier detection
• BREAKING CHANGE: Remove unused run_paused/run_resumed events and paused status

This makes the system faster, easier to reason about, and resilient to data inconsistencies.

Test plan

• TypeScript compiles
• Unit tests pass
• E2E tests pass

🤖 Generated with Claude Code

[changeset-bot]

🦋 Changeset detected

Latest commit: 9d01b15

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 19 packages

Name	Type
@workflow/core	Patch
@workflow/world	Patch
@workflow/world-local	Patch
@workflow/world-postgres	Patch
@workflow/world-vercel	Patch
@workflow/web-shared	Patch
@workflow/errors	Patch
@workflow/cli	Patch
@workflow/web	Patch
@workflow/builders	Patch
@workflow/docs-typecheck	Patch
@workflow/next	Patch
@workflow/nitro	Patch
workflow	Patch
@workflow/world-testing	Patch
@workflow/astro	Patch
@workflow/sveltekit	Patch
@workflow/nuxt	Patch
@workflow/ai	Patch

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[vercel]

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Project	Deployment	Review	Updated (UTC)
example-nextjs-workflow-turbopack	Ready	Preview, Comment	Jan 6, 2026 6:15pm
example-nextjs-workflow-webpack	Ready	Preview, Comment	Jan 6, 2026 6:15pm
example-workflow	Ready	Preview, Comment	Jan 6, 2026 6:15pm
workbench-astro-workflow	Ready	Preview, Comment	Jan 6, 2026 6:15pm
workbench-express-workflow	Ready	Preview, Comment	Jan 6, 2026 6:15pm
workbench-fastify-workflow	Ready	Preview, Comment	Jan 6, 2026 6:15pm
workbench-hono-workflow	Ready	Preview, Comment	Jan 6, 2026 6:15pm
workbench-nitro-workflow	Ready	Preview, Comment	Jan 6, 2026 6:15pm
workbench-nuxt-workflow	Ready	Preview, Comment	Jan 6, 2026 6:15pm
workbench-sveltekit-workflow	Ready	Preview, Comment	Jan 6, 2026 6:15pm
workbench-vite-workflow	Ready	Preview, Comment	Jan 6, 2026 6:15pm

1 Skipped Deployment

Project	Deployment	Review	Updated (UTC)
workflow-docs	Skipped		Jan 6, 2026 6:15pm

[github-actions]

🧪 E2E Test Results

❌ Some tests failed

Summary

	Passed	Failed	Skipped	Total
✅ ▲ Vercel Production	374	0	11	385
✅ 💻 Local Development	342	0	8	350
✅ 📦 Local Production	342	0	8	350
✅ 🐘 Local Postgres	342	0	8	350
✅ 🪟 Windows	35	0	0	35
❌ 🌍 Community Worlds	24	128	0	152
Total	1459	128	35	1622

❌ Failed Tests

🌍 Community Worlds (128 failed)

mongodb (32 failed):

• addTenWorkflow
• addTenWorkflow
• should work with react rendering in step
• promiseAllWorkflow
• promiseRaceWorkflow
• promiseAnyWorkflow
• readableStreamWorkflow
• hookWorkflow
• webhookWorkflow
• sleepingWorkflow
• nullByteWorkflow
• workflowAndStepMetadataWorkflow
• outputStreamWorkflow
• outputStreamInsideStepWorkflow - getWritable() called inside step functions
• fetchWorkflow
• promiseRaceStressTestWorkflow
• error handling error propagation workflow errors nested function calls preserve message and stack trace
• error handling error propagation workflow errors cross-file imports preserve message and stack trace
• error handling error propagation step errors basic step error preserves message and stack trace
• error handling error propagation step errors cross-file step error preserves message and function names in stack
• error handling retry behavior regular Error retries until success
• error handling retry behavior FatalError fails immediately without retries
• error handling retry behavior RetryableError respects custom retryAfter delay
• error handling retry behavior maxRetries=0 disables retries
• error handling catchability FatalError can be caught and detected with FatalError.is()
• hookCleanupTestWorkflow - hook token reuse after workflow completion
• concurrent hook token conflict - two workflows cannot use the same hook token simultaneously
• stepFunctionPassingWorkflow - step function references can be passed as arguments (without closure vars)
• stepFunctionWithClosureWorkflow - step function with closure variables passed as argument
• closureVariableWorkflow - nested step functions with closure variables
• spawnWorkflowFromStepWorkflow - spawning a child workflow using start() inside a step
• pathsAliasWorkflow - TypeScript path aliases resolve correctly

redis (32 failed):

• addTenWorkflow
• addTenWorkflow
• should work with react rendering in step
• promiseAllWorkflow
• promiseRaceWorkflow
• promiseAnyWorkflow
• readableStreamWorkflow
• hookWorkflow
• webhookWorkflow
• sleepingWorkflow
• nullByteWorkflow
• workflowAndStepMetadataWorkflow
• outputStreamWorkflow
• outputStreamInsideStepWorkflow - getWritable() called inside step functions
• fetchWorkflow
• promiseRaceStressTestWorkflow
• error handling error propagation workflow errors nested function calls preserve message and stack trace
• error handling error propagation workflow errors cross-file imports preserve message and stack trace
• error handling error propagation step errors basic step error preserves message and stack trace
• error handling error propagation step errors cross-file step error preserves message and function names in stack
• error handling retry behavior regular Error retries until success
• error handling retry behavior FatalError fails immediately without retries
• error handling retry behavior RetryableError respects custom retryAfter delay
• error handling retry behavior maxRetries=0 disables retries
• error handling catchability FatalError can be caught and detected with FatalError.is()
• hookCleanupTestWorkflow - hook token reuse after workflow completion
• concurrent hook token conflict - two workflows cannot use the same hook token simultaneously
• stepFunctionPassingWorkflow - step function references can be passed as arguments (without closure vars)
• stepFunctionWithClosureWorkflow - step function with closure variables passed as argument
• closureVariableWorkflow - nested step functions with closure variables
• spawnWorkflowFromStepWorkflow - spawning a child workflow using start() inside a step
• pathsAliasWorkflow - TypeScript path aliases resolve correctly

starter (32 failed):

• addTenWorkflow
• addTenWorkflow
• should work with react rendering in step
• promiseAllWorkflow
• promiseRaceWorkflow
• promiseAnyWorkflow
• readableStreamWorkflow
• hookWorkflow
• webhookWorkflow
• sleepingWorkflow
• nullByteWorkflow
• workflowAndStepMetadataWorkflow
• outputStreamWorkflow
• outputStreamInsideStepWorkflow - getWritable() called inside step functions
• fetchWorkflow
• promiseRaceStressTestWorkflow
• error handling error propagation workflow errors nested function calls preserve message and stack trace
• error handling error propagation workflow errors cross-file imports preserve message and stack trace
• error handling error propagation step errors basic step error preserves message and stack trace
• error handling error propagation step errors cross-file step error preserves message and function names in stack
• error handling retry behavior regular Error retries until success
• error handling retry behavior FatalError fails immediately without retries
• error handling retry behavior RetryableError respects custom retryAfter delay
• error handling retry behavior maxRetries=0 disables retries
• error handling catchability FatalError can be caught and detected with FatalError.is()
• hookCleanupTestWorkflow - hook token reuse after workflow completion
• concurrent hook token conflict - two workflows cannot use the same hook token simultaneously
• stepFunctionPassingWorkflow - step function references can be passed as arguments (without closure vars)
• stepFunctionWithClosureWorkflow - step function with closure variables passed as argument
• closureVariableWorkflow - nested step functions with closure variables
• spawnWorkflowFromStepWorkflow - spawning a child workflow using start() inside a step
• pathsAliasWorkflow - TypeScript path aliases resolve correctly

turso (32 failed):

• addTenWorkflow
• addTenWorkflow
• should work with react rendering in step
• promiseAllWorkflow
• promiseRaceWorkflow
• promiseAnyWorkflow
• readableStreamWorkflow
• hookWorkflow
• webhookWorkflow
• sleepingWorkflow
• nullByteWorkflow
• workflowAndStepMetadataWorkflow
• outputStreamWorkflow
• outputStreamInsideStepWorkflow - getWritable() called inside step functions
• fetchWorkflow
• promiseRaceStressTestWorkflow
• error handling error propagation workflow errors nested function calls preserve message and stack trace
• error handling error propagation workflow errors cross-file imports preserve message and stack trace
• error handling error propagation step errors basic step error preserves message and stack trace
• error handling error propagation step errors cross-file step error preserves message and function names in stack
• error handling retry behavior regular Error retries until success
• error handling retry behavior FatalError fails immediately without retries
• error handling retry behavior RetryableError respects custom retryAfter delay
• error handling retry behavior maxRetries=0 disables retries
• error handling catchability FatalError can be caught and detected with FatalError.is()
• hookCleanupTestWorkflow - hook token reuse after workflow completion
• concurrent hook token conflict - two workflows cannot use the same hook token simultaneously
• stepFunctionPassingWorkflow - step function references can be passed as arguments (without closure vars)
• stepFunctionWithClosureWorkflow - step function with closure variables passed as argument
• closureVariableWorkflow - nested step functions with closure variables
• spawnWorkflowFromStepWorkflow - spawning a child workflow using start() inside a step
• pathsAliasWorkflow - TypeScript path aliases resolve correctly

Details by Category

✅ ▲ Vercel Production

App	Passed	Failed	Skipped
✅ astro	34	0	1
✅ example	34	0	1
✅ express	34	0	1
✅ fastify	34	0	1
✅ hono	34	0	1
✅ nextjs-turbopack	34	0	1
✅ nextjs-webpack	34	0	1
✅ nitro	34	0	1
✅ nuxt	34	0	1
✅ sveltekit	34	0	1
✅ vite	34	0	1

✅ 💻 Local Development

App	Passed	Failed	Skipped
✅ astro-stable	34	0	1
✅ express-stable	34	0	1
✅ fastify-stable	34	0	1
✅ hono-stable	34	0	1
✅ nextjs-turbopack-stable	35	0	0
✅ nextjs-webpack-stable	35	0	0
✅ nitro-stable	34	0	1
✅ nuxt-stable	34	0	1
✅ sveltekit-stable	34	0	1
✅ vite-stable	34	0	1

✅ 📦 Local Production

App	Passed	Failed	Skipped
✅ astro-stable	34	0	1
✅ express-stable	34	0	1
✅ fastify-stable	34	0	1
✅ hono-stable	34	0	1
✅ nextjs-turbopack-stable	35	0	0
✅ nextjs-webpack-stable	35	0	0
✅ nitro-stable	34	0	1
✅ nuxt-stable	34	0	1
✅ sveltekit-stable	34	0	1
✅ vite-stable	34	0	1

✅ 🐘 Local Postgres

App	Passed	Failed	Skipped
✅ astro-stable	34	0	1
✅ express-stable	34	0	1
✅ fastify-stable	34	0	1
✅ hono-stable	34	0	1
✅ nextjs-turbopack-stable	35	0	0
✅ nextjs-webpack-stable	35	0	0
✅ nitro-stable	34	0	1
✅ nuxt-stable	34	0	1
✅ sveltekit-stable	34	0	1
✅ vite-stable	34	0	1

✅ 🪟 Windows

App	Passed	Failed	Skipped
✅ nextjs-turbopack	35	0	0

❌ 🌍 Community Worlds

App	Passed	Failed	Skipped
✅ mongodb-dev	3	0	0
❌ mongodb	3	32	0
✅ redis-dev	3	0	0
❌ redis	3	32	0
✅ starter-dev	3	0	0
❌ starter	3	32	0
✅ turso-dev	3	0	0
❌ turso	3	32	0

---

📋 View full workflow run

[pranaygp]

• perf: add events.createBatch() for batch event creation #641
• implement event-sourced architecture #621 👈 (View in Graphite)
• perf: parallelize suspension handler for high-concurrency #544 : 1 other dependent PR (#620 )
• perf: use Map for invocationsQueue (O(1) lookup/delete) #541
• Add stress test benchmarks for large concurrent step counts #539
• main

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[Copilot]

Pull request overview

This PR introduces a performance optimization for event creation by adding a createBatch() method to the World interface. The implementation enables atomic batch creation of multiple events, significantly improving the wait completion logic in the runtime from O(n²) to O(n) complexity.

Key Changes

• Added events.createBatch() method to the World interface for creating multiple events in a single operation
• Implemented batch creation across three storage backends (world-vercel, world-postgres, world-local) with backend-specific optimizations
• Optimized runtime wait completion logic using Set-based correlation ID lookup and batch event creation

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 8 comments.

Show a summary per file

File	Description
packages/world/src/interfaces.ts	Added createBatch() method signature with JSDoc documentation to the Storage events interface
packages/world-vercel/src/storage.ts	Integrated batch event creation into the storage adapter
packages/world-vercel/src/events.ts	Implemented createWorkflowRunEventBatch() using parallel API calls via Promise.all
packages/world-postgres/src/storage.ts	Implemented batch creation using a single INSERT query with multiple values for optimal database performance
packages/world-local/src/storage.ts	Implemented sequential batch creation to maintain monotonic ULID ordering for filesystem storage
packages/core/src/runtime.ts	Refactored wait completion to use Set-based lookup and batch event creation, improving from O(n²) to O(n) complexity
.changeset/brave-dots-bake.md	Added changeset documenting the performance improvement across all affected packages

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