docs(serverless): document timeout tuning

[NathanFlurry]

Description

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• 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

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• My code follows the style guidelines of this project
• I have performed a self-review of my code
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• I have made corresponding changes to the documentation
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[NathanFlurry]

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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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• TODO: ktichen sink counter latency #5051
• fix(rivetkit): use engine actor stop threshold for shutdown #5049
• DO NOT MERGE: serverless restart race condition #4997
• fix(rivetkit): exit pid1 after signal shutdown #5045
• fix(rivetkit-core): decrement active actor metrics #5044
• fix(envoy-client): dont abort drain after 20s #5043
• temp: patch wasm-pack to point to latest binary #5037
• fix(rivetkit): require engine ping for health #5022
• feat(rivetkit): add current actor metrics #5020
• feat(rivetkit): expose low-cardinality metrics routes #5019
• docs(serverless): document timeout tuning #5018 👈 (View in Graphite)
• feat(kitchen-sink): add load testing harness #5017
• fix(rivetkit): expose client actor metadata #5016
• fix(runtime): avoid bounded dispatch channel stalls #5015
• fix(sqlite): fence remote requests by generation #5014
• feat(rivetkit-core): expose metrics endpoint #5013
• WIP: counter latency monitor #5011
• main

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[claude]

Code Review: docs(serverless): document timeout tuning

Overview: Small docs-only PR that improves the serverless production checklist with clearer, more actionable guidance on concurrency caps, requestLifespan, and drainGracePeriod tuning. Also appends driver test re-run results to the agent notes file.

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.agent/notes/driver-test-progress.md

No concerns — log entries follow the existing format and all 6 DB file groups are reported as passing.

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website/src/content/docs/general/production-checklist.mdx

Positive changes:

• The rewritten concurrency bullet is a clear improvement. It explains why per-instance concurrency matters (one actor per in-flight /api/rivet/start) and names concrete platform knobs (--concurrency, reserved concurrency, maxDuration).
• Adding separate bullets for requestLifespan and drainGracePeriod surfaces tuning that was previously invisible to operators — good addition.

Issues to verify:

1. Vercel tier values look swapped. The bullet reads 295 for Vercel Hobby, 3595 for Vercel Pro. Vercel Hobby serverless functions have a 60-second hard timeout, not ~300 s. 295 s is 5 s below Vercel Pro's 300 s limit. Consider double-checking and using something like:

   • Hobby: 55 (below the 60 s cap)
   • Pro: 295 (below the 300 s cap)
   • Enterprise/streaming: 3595 (if applicable)
     Using the wrong value could cause operators on Hobby to set a requestLifespan that exceeds their actual platform limit, resulting in forcibly killed requests.

2. AWS Lambda reserved concurrency framing. The bullet groups "AWS Lambda reserved concurrency" under the per-instance concurrency examples. Lambda reserved concurrency is a total concurrent-execution cap across all instances, not a per-instance setting. The most relevant Lambda knob is that Lambda is inherently single-threaded (one event at a time per instance), so per-instance concurrency is always 1. This could mislead Lambda users. Consider either dropping the Lambda example or clarifying that Lambda concurrency is always 1 per instance by default.

3. drainGracePeriod default. The bullet says "Default is 30 minutes from the engine". If this differs from the value surfaced by configurePool or the value a user would see in generated docs, it may cause confusion. Worth confirming the canonical default before merge.

4. Link validity. The requestLifespan bullet links to /docs/general/runtime-modes#timeouts and the drainGracePeriod bullet links to /docs/actors/limits. If those anchors or pages do not exist yet, the links will 404. Worth verifying both resolve correctly.

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Summary: The intent and structure of these docs improvements are solid. The main thing to address before merge is the Vercel Hobby timeout value — using an incorrect example there is the most likely source of real operator pain.