feat(rivetkit/effect): effect support #4009

NathanFlurry · 2026-01-22T08:12:29Z

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railway-app · 2026-01-22T08:12:37Z

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NathanFlurry · 2026-01-22T08:12:45Z

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feat(rivetkit/effect): effect support #4009 👈 (View in Graphite)
feat(examples): effect #4008
feat(rivetkit): add actor run handler #4005 : 1 other dependent PR (#3734 )
feat: actor messages & queues #3989 : 1 other dependent PR (#4002 )
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claude · 2026-01-22T08:16:27Z

Effect Integration Review

This PR adds comprehensive Effect.ts integration to RivetKit, enabling functional programming patterns with robust error handling. Overall, the implementation is well-structured and follows Effect best practices. Here are my findings:

✅ Strengths

Clean Architecture
- Well-organized namespace pattern for lifecycle hooks (e.g., OnCreate, OnWake, Run)
- Consistent API design across all Effect wrappers
- Good separation between core integration (rivetkit-typescript/packages/effect) and examples
Type Safety
- Proper use of Effect's type system with generic constraints
- Correct YieldWrap usage for Effect generators
- Type-safe context propagation via ActorContextTag
Good Examples
- fetch-actor.ts demonstrates multi-step workflows with error handling
- queue-processor.ts shows long-running background processing patterns
- Examples use proper Effect patterns like Effect.either for error recovery
Test Coverage
- Basic test coverage for Effect-wrapped actors
- Tests verify state management and broadcasting work correctly

🔍 Issues & Concerns

Critical Issues

1. Missing Error Handling in waitUntil (rivetkit-typescript/packages/effect/src/actor.ts:282-283)

The .then(() => {}) swallows errors from the Effect execution. If the Effect fails, the error is silently lost.

Recommendation: Handle errors explicitly or let them propagate.

2. Unsafe Type Casts (rivetkit-typescript/packages/effect/src/actor.ts:187, 213, etc.)

Multiple instances of (c as any) casts, particularly around c.queue access. This bypasses type safety.

Recommendation: Define proper types for queue context or use type guards.

Medium Priority Issues

3. Inconsistent waitUntil Usage

actor.ts:effect() (lines 282-283) uses waitUntil for durability
action.ts:effect() (line 55) does NOT use waitUntil

Question: Is this intentional? If actions need durability, they should also use waitUntil. If not, document why.

4. Queue Type Safety (rivetkit-typescript/packages/effect/src/queue.ts)

The queue property is accessed via type cast. This should be properly typed.

5. Test Coverage Gaps

No tests for lifecycle hooks (OnCreate, OnDestroy, etc.)
No tests for error scenarios
No tests for queue processing

Recommendation: Add tests for error propagation through Effect chains and lifecycle hook execution order.

Minor Issues

6. Missing JSDoc Comments

Core utilities like effect(), updateState(), etc. lack documentation.

7. Duplicate effect Function

Defined in both actor.ts (line 247) and action.ts (line 18). The action.ts version accepts variadic args, actor.ts doesn't.

📝 Code Quality Observations

Following CLAUDE.md Guidelines ✅

✅ Imports at top of file (not inline)
✅ Lowercase log messages
✅ Good structured logging with context objects
✅ Uses workspace dependencies (effect as peer dependency)

📋 Recommendations Summary

Must Fix (Before Merge):

Fix error handling in waitUntil (actor.ts:282-283)
Remove or properly type all as any casts
Clarify waitUntil usage consistency between actor/action effects

Should Fix (Before Merge):
4. Add JSDoc documentation to public APIs
5. Improve test coverage (lifecycle, errors, queues)

Nice to Have:
6. Strengthen ActorContextTag typing
7. Document performance characteristics
8. Add examples for error recovery patterns

✅ Overall Assessment

This is a solid foundation for Effect integration. The API design is clean and follows Effect conventions well. The main concerns are around error handling safety and type safety with the as any casts. Once those are addressed, this will be a valuable addition to RivetKit.

Recommendation: Request changes for critical issues, then approve after fixes.

Review generated by Claude Code - Analyzed 32 files with focus on rivetkit-typescript/packages/effect/

pkg-pr-new · 2026-01-22T08:45:22Z

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commit: 3bc91d9

graphite-app · 2026-01-22T09:46:40Z

examples/effect/src/actors/queue-processor.ts

+import { Effect } from "effect";
+import { actor } from "rivetkit";
+import { Action, Run, Log, Queue } from "@rivetkit/effect";


The imports should be sorted alphabetically to comply with Biome linter rules. Change to: import { Action, Log, Queue, Run } from '@rivetkit/effect'; import { Effect } from 'effect'; import { actor } from 'rivetkit';

Spotted by Graphite Agent (based on CI logs)

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graphite-app · 2026-01-22T09:53:23Z

examples/effect/src/actors/fetch-actor.ts

+import { Data, Effect } from "effect";
+import { actor } from "rivetkit";
+import { Action, Log } from "@rivetkit/effect";


Import sorting issue. Reorder imports to follow the project's convention: third-party imports first (alphabetically), then local imports.

Spotted by Graphite Agent (based on CI logs)

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NathanFlurry mentioned this pull request Jan 22, 2026

feat(examples): effect #4008

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feat(rivetkit/effect): effect support

3bc91d9

NathanFlurry force-pushed the 01-22-feat_rivetkit_effect_effect_support branch from acb5eb3 to 3bc91d9 Compare January 22, 2026 08:42

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Effect Integration Review

✅ Strengths

🔍 Issues & Concerns

Critical Issues

Medium Priority Issues

Minor Issues

📝 Code Quality Observations

Following CLAUDE.md Guidelines ✅

📋 Recommendations Summary

✅ Overall Assessment

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