fix(rivetkit): warn when manager port falls back to a different port

[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-4489 environment in rivet-frontend

Service	Status	Web	Updated (UTC)
website	✅ Success (View Logs)	Web	Mar 24, 2026 at 1:20 pm
frontend-cloud	😴 Sleeping (View Logs)	Web	Mar 24, 2026 at 1:02 pm
frontend-inspector	😴 Sleeping (View Logs)	Web	Mar 24, 2026 at 11:53 am
kitchen-sink	❌ Build Failed (View Logs)	Web	Mar 24, 2026 at 11:34 am
ladle	❌ Build Failed (View Logs)	Web	Mar 24, 2026 at 1:58 am
mcp-hub	✅ Success (View Logs)	Web	Mar 24, 2026 at 1:54 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): setup database before lifecycle hooks for c.db availability #4494
• fix(rivetkit): remove drizzle-orm peer dep and add runtime version check #4492
• chore(skill): add version check to rivetkit skill #4491
• fix(rivetkit): prevent Turbopack from tracing sqlite-vfs dynamic import #4490
• fix(rivetkit): warn when manager port falls back to a different port #4489 👈 (View in Graphite)
• fix(rivetkit): clear connectableTs on actor sleep #4488
• fix(rivetkit): gate node:sqlite behind RIVETKIT_NODE_SQLITE env var #4487
• main

This stack of pull requests is managed by Graphite. Learn more about stacking.

[claude]

PR Review: fix(rivetkit): warn when manager port falls back to a different port

This is a small, focused change that adds a warning log when findFreePort returns a different port than the configured one. The intent is correct and addresses a real UX gap - port fallback previously happened silently.

Feedback

Structured logging

The warning interpolates port numbers directly into the msg string. Per the project structured logging convention in CLAUDE.md, parameters should not be formatted into the main message - they should be separate fields. This is also consistent with the adjacent logger().debug() call below it, which already uses named fields (port: managerPort).

Current code uses: msg interpolated with configuredManagerPort and managerPort.

Suggested approach: use msg set to "manager port is in use, falling back to a different port" with configuredPort and actualPort as separate named fields.

This makes the port values queryable and filterable in log aggregation tools.

Summary

The change is correct and well-placed. The only suggested improvement is separating the port values into named structured fields rather than interpolating them into the message string.