playbook/antigravity-awesome-skills/skills/vercel-optimize/references/support-topics/function-region-misconfiguration-ttfb.md

id	title	status	candidateKinds	frameworks	scannerPatterns	priority	citations	maxBriefChars
function-region-misconfiguration-ttfb	Function region misconfiguration (TTFB)	active	region_misconfig	*	region-pin-in-config	85	https://vercel.com/docs/functions/configuring-functions/region https://vercel.com/docs/regions	950

Investigation Brief

A single function region is pinned. Per-region TTFB data is unavailable today (evidence.dataGap); treat as an audit prompt — validate the pinned region against user geo and data-source location before recommending changes.

Evidence To Check

Scanner subtype (vercel-json-single, segment-preferred) and pinned regions. Cross-check Speed Insights TTFB and country analytics for traffic geo. Locate the data source — proximity to it often wins on cache-miss paths.

Do Not Recommend When

Skip if TTFB is healthy across countries. Skip if pinned intentionally for data proximity. Skip on small projects (<20 routes). Do not propose multi-region without confirming the data layer is reachable without cross-region egress.

Verification

Name pinned region(s), traffic geo, data-source location, and a specific call: relocate, expand, or keep with a TTFB monitor.