chore: fix serverless in rivetkit-core

[NathanFlurry]

Description

Please include a summary of the changes and the related issue. Please also include relevant motivation and context.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[railway-app]

🚅 Deployed to the rivet-pr-4719 environment in rivet-frontend

Service	Status	Web	Updated (UTC)
kitchen-sink	❌ Build Failed (View Logs)	Web	Apr 24, 2026 at 6:02 am
website	😴 Sleeping (View Logs)	Web	Apr 24, 2026 at 1:49 am
frontend-cloud	❌ Build Failed (View Logs)	Web	Apr 24, 2026 at 1:42 am
ladle	✅ Success (View Logs)	Web	Apr 24, 2026 at 1:42 am
frontend-inspector	❌ Build Failed (View Logs)	Web	Apr 24, 2026 at 1:42 am
mcp-hub	✅ Success (View Logs)	Web	Apr 24, 2026 at 1:41 am

[NathanFlurry]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
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• fix(rivetkit): drop is_read_only_sql classifier, surface RETURNING rows #4728
• docs: require close-code rejection for websocket auth/policy failures #4727
• fix(rivetkit): inspector reports actual config state + real queue messages #4726
• fix(rivetkit-napi): plumb ctx through serializeState TSF and stop panicking on runtime_state Ref drop #4725
• chore(rivetkit): remove legacy metrics & prometheus auth #4724
• chore(rivetkit): remove legacy metrics #4723
• chore(rivetkit): impl inspector token #4722
• chore: disable auth on serverless #4721
• chore: fix cors for envoys #4720
• chore: fix serverless in rivetkit-core #4719 👈 (View in Graphite)
• chore(rivetkit): impl follow up review #4711
• chore: rivetkit core/napi/typescript follow up review #4702
• chore: fix remaining issues with rivetkit-core #4701
• feat: import/export actors #4640
• chore: sqlite v1 to v2 data migration #4692
• chore: move rivetkit to task model #4680
• chore: rivetkit to rust #4679
• feat(rivetkit): sqlite vfs v2 #4673
• chore: rename sandbox -> kitchen sink #4671 : 1 other dependent PR (#4672 )
• chore: configure TLS trust roots for rustls clients #4667
• fix(rivetkit): update config to match envoys & remove manager references #4663
• chore(publish): pin docker base image refs #4652
• chore(engine): publish engine bases in ci #4649 : 2 other dependent PRs (#4650 , #4666 )
• chore: lockfile lefthook #4647
• fix(rivetkit): surface native sqlite kv errors to callers #4645
• fix(rivetkit): prevent sleep races during disconnect and db work #4644
• fix(rivetkit): isolate engine envoys and propagate startup failures #4643
• test(rivetkit): remove wasm sqlite-only fixtures and coverage #4642
• chore(sqlite-vfs): remove wasm sqlite packages and workspace wiring #4641
• chore(rivetkit): remove wasm sqlite runtime #4614
• fix(sqlite-native): restore native startup kv preload #4639
• fix(sqlite-native): delete metadata before chunk range #4638
• fix(sqlite-native): keep truncate cache coherent #4637
• fix(sqlite-vfs): use delete range for truncate cleanup #4636
• fix(sqlite-native): restore kv error hook #4635
• perf(sqlite-native): avoid cloning cached read chunks #4634
• perf(sqlite-native): gate kv operation labels #4633
• perf(sqlite-native): reuse read cache for partial writes #4632
• perf(sqlite-native): remove delete file existence probe #4631
• fix(sqlite-native): gate native read cache behind env var #4630
• fix(pegboard): isolate runner config dc lookup failures #4625 : 1 other dependent PR (#4626 )
• docs(pegboard): note runner config upsert split write risk #4624
• fix(pegboard): unpack global runner config keys correctly #4623
• fix(pegboard-gateway): enforce tunnel message state #4622
• fix(pegboard-runner): clear terminal tunnel routes #4621
• fix(pegboard): skip protocol version keys in runner pool backfill #4620
• fix(pegboard): create missing normal runner configs #4619
• fix(epoxy): reuse cached optimistic value #4618
• main

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[claude]

PR Review: chore: fix serverless in rivetkit-core

Overview

This PR extracts shared serverless metadata types into a new rivetkit-shared-types crate to eliminate duplication between rivetkit-core and engine/packages/pegboard. It also improves error handling in the metadata fetch path, simplifies the NAPI build script, and updates the kitchen-sink example to use a published @rivetkit/sql-loader package.

---

Issues

Silent serialization failure (serverless.rs)

let mut response = serde_json::to_value(payload).unwrap_or_else(|_| json!({}));

If serde_json::to_value fails, this returns an empty JSON object, silently discarding all actor names and metadata without any log or error. Since ServerlessMetadataPayload only contains serializable primitives and serde_json::Value, serialization should not realistically fail — but if it does, this will produce a subtly broken response rather than a visible error. Prefer expect() with a message or proper ? propagation.

Post-processing to inject kind and drop null runner (serverless.rs)

The kind: {"serverless": {}} field is injected into the serialized JSON after the fact because it is not part of ServerlessMetadataPayload:

if let Some(envoy) = object.get_mut("envoy").and_then(|v| v.as_object_mut()) {
    envoy.insert("kind".to_owned(), json!({ "serverless": {} }));
}

Similarly, the null runner field is manually stripped after serialization. Both are workarounds for struct design. Two cleaner options:

• Add a kind field to ServerlessMetadataEnvoy using a typed enum.
• Annotate the runner field with #[serde(skip_serializing_if = "Option::is_none")] so it never appears in serialized output. If deserialization symmetry is needed, this is still safe — a missing field deserializes to None when default is used.

This would eliminate the post-serialization mutation entirely.

NAPI build: pre-built artifact detection removed

The previous build script skipped the napi build if a pre-built .node file existed, allowing CI to skip a redundant native compile when cross-compiled artifacts were already downloaded. That logic is now gone. If CI no longer provides pre-built artifacts, the removal is fine — but the PR description does not explain why. Worth confirming this does not regress CI build times.

Turbo.json glob inputs may cause excessive cache misses

../../../Cargo.lock is now an input, meaning any dependency update in the workspace (even unrelated crates) invalidates the Turbo cache for rivetkit-napi. The **/ globs across all of rivetkit-rust/packages and engine/packages have the same effect. This is more correct than before (previously rivetkit-core changes would not trigger a rebuild) but may cause more frequent full rebuilds in CI.

@rivetkit/sql-loader resolves to npm, not the workspace

pnpm-lock.yaml pins @rivetkit/sql-loader to the published version 2.2.1. If rivetkit-typescript/packages/sql-loader exists in the monorepo, this should use workspace:* so the kitchen-sink example always tests the local version. If the package is intentionally external-only, that is fine but worth noting explicitly.

---

Positives

• Good deduplication. Extracting ServerlessMetadataPayload and friends into rivetkit-shared-types is the right call. The previous state had two private copies of the same structs.
• Better error hygiene. Adding parse_error: String to InvalidResponseJson and introducing the dedicated InvalidEnvoyProtocolVersion variant (previously misreported as InvalidResponseJson) are clear improvements for observability.
• execFileSync over execSync. Using execFileSync avoids shell injection and is the correct API when arguments are known at call time.
• Turbo inputs now includes scripts/build.mjs and build.rs. Previously missing; changes to the build script now correctly invalidate the Turbo cache.

---

Minor Notes

• ServerlessMetadataRunner is defined in shared-types but runner: None is always set at the call site in serverless.rs. If runner support is not planned, consider whether the field is needed in the shared struct at all.
• The new shared-types crate has no [lib] section in Cargo.toml, which defaults correctly to src/lib.rs — fine as-is.
• If you keep the unwrap_or_else fallback, at minimum log the error before falling back to json!({}) so failures are not completely silent.

[github-actions]

Preview packages published to npm

Install with:

npm install rivetkit@pr-4719

All packages published as 0.0.0-pr.4719.23ea795 with tag pr-4719.

Engine binary is shipped via @rivetkit/engine-cli on linux-x64-musl, linux-arm64-musl, darwin-x64, and darwin-arm64. Windows users should use the release installer or set RIVET_ENGINE_BINARY.

Docker images:

docker pull rivetdev/engine:slim-23ea795
docker pull rivetdev/engine:full-23ea795

Individual packages

npm install rivetkit@pr-4719
npm install @rivetkit/react@pr-4719
npm install @rivetkit/rivetkit-napi@pr-4719
npm install @rivetkit/workflow-engine@pr-4719