Enable custom class serialization transformations for "client" mode

[TooTallNate]

Enable class serialization in client mode to support passing class instances to workflow functions.

What changed?

• Added support for class serialization transformations in "client" mode
• The plugin now generates necessary imports and registration calls for classes that need serialization in client mode
• When classes are detected that need serialization, the plugin:
  • Imports registerSerializationClass from "workflow/internal/class-serialization"
  • Adds registration calls for each class with a unique class ID
• Updated test outputs to reflect these changes

How to test?

1. Create a class with serialization methods (using WORKFLOW_SERIALIZE and WORKFLOW_DESERIALIZE symbols)
2. Use the class in a client-side context where it's passed to a workflow function
3. Verify that the class is properly serialized and deserialized when passed between client and workflow

Why make this change?

Previously, class serialization was only enabled in workflow mode, which meant that classes couldn't be properly serialized when passed from client code to workflow functions. This change ensures that classes with custom serialization methods work correctly when used as arguments to start(workflow) calls from client code.

[changeset-bot]

🦋 Changeset detected

Latest commit: 1a72c70

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

This PR includes changesets to release 15 packages

Name	Type
@workflow/swc-plugin	Patch
@workflow/astro	Patch
@workflow/builders	Patch
@workflow/cli	Patch
@workflow/nest	Patch
@workflow/next	Patch
@workflow/nitro	Patch
@workflow/rollup	Patch
@workflow/sveltekit	Patch
workflow	Patch
@workflow/world-testing	Patch
@workflow/example-nest	Patch
@workflow/docs-typecheck	Patch
@workflow/nuxt	Patch
@workflow/ai	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[github-actions]

🧪 E2E Test Results

❌ Some tests failed

Summary

	Passed	Failed	Skipped	Total
✅ ▲ Vercel Production	457	0	38	495
❌ 💻 Local Development	416	2	32	450
✅ 📦 Local Production	418	0	32	450
✅ 🐘 Local Postgres	418	0	32	450
✅ 🪟 Windows	45	0	0	45
❌ 🌍 Community Worlds	31	161	0	192
✅ 📋 Other	123	0	12	135
Total	1908	163	146	2217

❌ Failed Tests

💻 Local Development (2 failed)

astro-stable (2 failed):

• 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

🌍 Community Worlds (161 failed)

mongodb (40 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
• Calculator.calculate - static workflow method using static step methods from another class
• AllInOneService.processNumber - static workflow method using sibling static step methods
• ChainableService.processWithThis - static step methods using this to reference the class
• thisSerializationWorkflow - step function invoked with .call() and .apply()
• customSerializationWorkflow - custom class serialization with WORKFLOW_SERIALIZE/WORKFLOW_DESERIALIZE
• pages router addTenWorkflow via pages router
• pages router promiseAllWorkflow via pages router
• pages router sleepingWorkflow via pages router

redis (40 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
• Calculator.calculate - static workflow method using static step methods from another class
• AllInOneService.processNumber - static workflow method using sibling static step methods
• ChainableService.processWithThis - static step methods using this to reference the class
• thisSerializationWorkflow - step function invoked with .call() and .apply()
• customSerializationWorkflow - custom class serialization with WORKFLOW_SERIALIZE/WORKFLOW_DESERIALIZE
• pages router addTenWorkflow via pages router
• pages router promiseAllWorkflow via pages router
• pages router sleepingWorkflow via pages router

starter (41 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
• health check (CLI) - workflow health command reports healthy endpoints
• pathsAliasWorkflow - TypeScript path aliases resolve correctly
• Calculator.calculate - static workflow method using static step methods from another class
• AllInOneService.processNumber - static workflow method using sibling static step methods
• ChainableService.processWithThis - static step methods using this to reference the class
• thisSerializationWorkflow - step function invoked with .call() and .apply()
• customSerializationWorkflow - custom class serialization with WORKFLOW_SERIALIZE/WORKFLOW_DESERIALIZE
• pages router addTenWorkflow via pages router
• pages router promiseAllWorkflow via pages router
• pages router sleepingWorkflow via pages router

turso (40 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
• Calculator.calculate - static workflow method using static step methods from another class
• AllInOneService.processNumber - static workflow method using sibling static step methods
• ChainableService.processWithThis - static step methods using this to reference the class
• thisSerializationWorkflow - step function invoked with .call() and .apply()
• customSerializationWorkflow - custom class serialization with WORKFLOW_SERIALIZE/WORKFLOW_DESERIALIZE
• pages router addTenWorkflow via pages router
• pages router promiseAllWorkflow via pages router
• pages router sleepingWorkflow via pages router

Details by Category

✅ ▲ Vercel Production

App	Passed	Failed	Skipped
✅ astro	41	0	4
✅ example	41	0	4
✅ express	41	0	4
✅ fastify	41	0	4
✅ hono	41	0	4
✅ nextjs-turbopack	44	0	1
✅ nextjs-webpack	44	0	1
✅ nitro	41	0	4
✅ nuxt	41	0	4
✅ sveltekit	41	0	4
✅ vite	41	0	4

❌ 💻 Local Development

App	Passed	Failed	Skipped
❌ astro-stable	39	2	4
✅ express-stable	41	0	4
✅ fastify-stable	41	0	4
✅ hono-stable	41	0	4
✅ nextjs-turbopack-stable	45	0	0
✅ nextjs-webpack-stable	45	0	0
✅ nitro-stable	41	0	4
✅ nuxt-stable	41	0	4
✅ sveltekit-stable	41	0	4
✅ vite-stable	41	0	4

✅ 📦 Local Production

App	Passed	Failed	Skipped
✅ astro-stable	41	0	4
✅ express-stable	41	0	4
✅ fastify-stable	41	0	4
✅ hono-stable	41	0	4
✅ nextjs-turbopack-stable	45	0	0
✅ nextjs-webpack-stable	45	0	0
✅ nitro-stable	41	0	4
✅ nuxt-stable	41	0	4
✅ sveltekit-stable	41	0	4
✅ vite-stable	41	0	4

✅ 🐘 Local Postgres

App	Passed	Failed	Skipped
✅ astro-stable	41	0	4
✅ express-stable	41	0	4
✅ fastify-stable	41	0	4
✅ hono-stable	41	0	4
✅ nextjs-turbopack-stable	45	0	0
✅ nextjs-webpack-stable	45	0	0
✅ nitro-stable	41	0	4
✅ nuxt-stable	41	0	4
✅ sveltekit-stable	41	0	4
✅ vite-stable	41	0	4

✅ 🪟 Windows

App	Passed	Failed	Skipped
✅ nextjs-turbopack	45	0	0

❌ 🌍 Community Worlds

App	Passed	Failed	Skipped
✅ mongodb-dev	3	0	0
❌ mongodb	5	40	0
✅ redis-dev	3	0	0
❌ redis	5	40	0
✅ starter-dev	3	0	0
❌ starter	4	41	0
✅ turso-dev	3	0	0
❌ turso	5	40	0

✅ 📋 Other

App	Passed	Failed	Skipped
✅ e2e-local-dev-nest-stable	41	0	4
✅ e2e-local-postgres-nest-stable	41	0	4
✅ e2e-local-prod-nest-stable	41	0	4

---

📋 View full workflow run

---

❌ Some E2E test jobs failed:

• Vercel Prod: success
• Local Dev: failure
• Local Prod: success
• Local Postgres: success
• Windows: success

Check the workflow run for details.

[vercel]

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Project	Deployment	Review	Updated (UTC)
example-nextjs-workflow-turbopack	Ready	Preview, Comment	Jan 27, 2026 7:00am
example-nextjs-workflow-webpack	Ready	Preview, Comment	Jan 27, 2026 7:00am
example-workflow	Ready	Preview, Comment	Jan 27, 2026 7:00am
workbench-astro-workflow	Ready	Preview, Comment	Jan 27, 2026 7:00am
workbench-express-workflow	Ready	Preview, Comment	Jan 27, 2026 7:00am
workbench-fastify-workflow	Ready	Preview, Comment	Jan 27, 2026 7:00am
workbench-hono-workflow	Ready	Preview, Comment	Jan 27, 2026 7:00am
workbench-nitro-workflow	Ready	Preview, Comment	Jan 27, 2026 7:00am
workbench-nuxt-workflow	Ready	Preview, Comment	Jan 27, 2026 7:00am
workbench-sveltekit-workflow	Ready	Preview, Comment	Jan 27, 2026 7:00am
workbench-vite-workflow	Ready	Preview, Comment	Jan 27, 2026 7:00am
workflow-docs	Ready	Preview, Comment	Jan 27, 2026 7:00am
workflow-nest	Error		Jan 27, 2026 7:00am

[TooTallNate]

• Enable custom class serialization transformations for "client" mode #860 👈 (View in Graphite)
• main

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[vercel]

🔧 Build Fix:

The OpenAI class is not constructable in the imported module. This is a type error where the code is trying to instantiate the OpenAI class, but the module export doesn't provide a constructor signature.