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 12:32 pm
website	✅ Success (View Logs)	Web	Apr 24, 2026 at 12:29 pm
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.
Learn more

• fix(rivetkit-core): gate startup until runtime is ready #4736 : 2 dependent PRs (#4737 , #4739 )
• fix(rivetkit-sqlite): preserve text with embedded nul bytes #4735
• chore(rivetkit): add child spans for logging #4734
• fix(rivetkit-core): orphan engine process and detect crashes #4733
• fix(rivetkit-core): return None for empty inspector state to avoid frontend CBOR decode error #4732
• fix(rivetkit-core): don't install tokio::signal::ctrl_c() handler inside serve_with_config #4731
• refactor(rivetkit-core): use subtle::ConstantTimeEq for inspector token verify #4730
• 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
• chore: sqlite v1 to v2 data migration #4692 : 1 other dependent PR (#4640 )
• 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 refactors the serverless metadata types by extracting shared Serde structs into a new rivetkit-shared-types crate, eliminating duplication between pegboard (engine) and rivetkit-core. It also improves error diagnostics, simplifies the NAPI build script, and broadens Turbo cache invalidation inputs.

---

Issues

Silent failure in serialization (rivetkit-rust/packages/rivetkit-core/src/serverless.rs)

The unwrap_or_else(|_| json!({})) on serialization silently returns {} on failure, which violates the fail-by-default principle from CLAUDE.md. This should either propagate as an error or log with tracing::error! before the fallback:

let mut response = match serde_json::to_value(payload) {
    Ok(v) => v,
    Err(err) => {
        tracing::error!(?err, "failed to serialize serverless metadata");
        return Err(anyhow::anyhow!("failed to serialize serverless metadata: {err}"));
    }
};

---

Manual null removal for runner (rivetkit-rust/packages/rivetkit-core/src/serverless.rs)

The post-serialization null check and removal for runner works around the default Option::None to null behavior. The idiomatic fix is #[serde(skip_serializing_if = "Option::is_none")] on the field in the shared types struct - safe since Option deserializes a missing field as None. This eliminates the need to patch the serialized map at all.

---

Typed struct approach is incomplete (rivetkit-rust/packages/rivetkit-core/src/serverless.rs)

The envoy.kind and clientEndpoint fields are still manually patched after serialization. Since the PR is moving to typed structs, consider adding a kind enum to ServerlessMetadataEnvoy and client_endpoint: Option<String> to ServerlessMetadataPayload. If this is deferred intentionally, a comment noting why would prevent future confusion.

---

build:force script silently ignores its flag (rivetkit-typescript/packages/rivetkit-napi/)

package.json still has "build:force": "node scripts/build.mjs --force", but the new build.mjs no longer parses --force. Since the prebuilt detection was removed entirely, build and build:force are now equivalent. CLAUDE.md still documents using build:force for native changes. Either remove build:force or keep it as an explicit alias and update the CLAUDE.md note.

---

Positive Changes

• Better error diagnostics: Adding parse_error: String to InvalidResponseJson and introducing a dedicated InvalidEnvoyProtocolVersion variant instead of reusing InvalidResponseJson for a version mismatch is a clear improvement.
• Deduplication via rivetkit-shared-types: Extracting the shared types into a minimal crate with only serde deps is the right approach. The crate follows workspace conventions correctly.
• Turbo cache inputs: Expanding inputs in rivetkit-napi/turbo.json to cover all dependent Rust crates prevents stale cache hits. The broader glob is appropriate given the new shared-types dependency.
• Build script simplification: Removing the prebuilt detection logic and relying on Turbos own caching is cleaner than the previous filesystem scanning approach.
• execFileSync over execSync: Safer approach that avoids shell interpretation of the command.

[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

[NathanFlurry]

Landed in main via stack-merge fast-forward push. Commits are in main; closing to match.