[slop]fix(rivetkit): surface raw error messages instead of generic

[abcxff]

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-4985 environment in rivet-frontend

Service	Status	Web	Updated (UTC)
kitchen-sink	❌ Build Failed (View Logs)	Web	May 7, 2026 at 5:08 pm
website	😴 Sleeping (View Logs)	Web	May 7, 2026 at 5:06 am
frontend-cloud	❌ Build Failed (View Logs)	Web	May 6, 2026 at 3:30 pm
frontend-inspector	❌ Build Failed (View Logs)	Web	May 6, 2026 at 3:30 pm
ladle	❌ Build Failed (View Logs)	Web	May 6, 2026 at 3:28 pm
mcp-hub	✅ Success (View Logs)	Web	May 6, 2026 at 3:28 pm

[abcxff]

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• [slop]fix(rivetkit): surface raw error messages instead of generic #4985 👈 (View in Graphite)
• [slop]fix(rivetkit): remove async drizzle db proxy #4984 : 2 other dependent PRs (#4986 , #4991 )
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[claude]

PR #4985 Review: fix(rivetkit): surface raw error messages instead of generic

This PR makes two changes: (1) always expose raw internal error messages in build_internal instead of gating them behind RIVET_EXPOSE_ERRORS=1, and (2) introduce a new sqlite.query_failed structured error code for SQL user errors (syntax errors, constraint violations, etc.) so they surface as typed 400 responses rather than raw anyhow errors.

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Issues Found

1. Security regression: internal errors always exposed (high severity)

build_internal previously gated raw error message exposure on RIVET_EXPOSE_ERRORS=1. Removing the gate means raw anyhow error messages (which can contain database connection strings, internal file paths, or other sensitive infrastructure details) are now always returned to any client receiving a core.internal_error response.

CLAUDE.md says: "The dev-mode toggle that exposes raw messages lives in core (reads env at build_internal), not in the TS bridge." This PR removes that toggle entirely. If intentional, the PR body should explain the rationale and the docs at website/src/content/docs/actors/errors.mdx and website/src/content/docs/general/production-checklist.mdx need updating.

2. SqliteWorkerCloseTimeoutError misclassified as a user SQL error (medium severity)

Before this PR, unrecognized errors in map_local_worker_error were passed through raw. After this PR they wrap as QueryFailed. But SqliteWorkerCloseTimeoutError is treated as fatal by is_fatal_worker_error yet is not matched in the Closed branch of map_local_worker_error. It therefore falls through to QueryFailed, which surfaces HTTP 400 to the caller, implying the user wrote a bad SQL query. This will mislead users debugging connectivity issues after an actor restart.

Fix: add SqliteWorkerCloseTimeoutError to the Closed branch to match the is_fatal_worker_error classification.

3. Missing trailing newline in artifact file (minor)

rivetkit-rust/engine/artifacts/errors/sqlite.query_failed.json is missing a trailing newline. If the artifact generator omits them for all files in that directory this is fine, but worth confirming.

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What Looks Good

• The SqliteRuntimeError::QueryFailed error type is well-designed: structured with a message field, correct HTTP 400 status, and an artifact file committed alongside the code change.
• public_error_status_code is correctly placed in rivetkit-core::error.
• No _ => enum fall-throughs, no Mutex<HashMap>, no eprintln!, no Box::leak per-request -- conventions are followed throughout.