docs-eas-env-drift

name	docs-eas-env-drift
version	0.1.0
description	Audit the "Built-in environment variables" list on the Expo docs EAS environment-variables usage page against the env definition sites in expo/eas-cli (report only, never edits docs). Use when the user asks whether the built-in EAS Build env vars are outdated, says "eas env drift", "check built-in env vars", or "/docs-eas-env-drift".
argument-hint	["path-to-expo-docs-checkout"]
allowed-tools	Read, Grep, Write, Bash(bun:*), Bash(git:*)

docs-eas-env-drift

The docs page pages/eas/environment-variables/usage.mdx lists the env vars EAS Build injects into every job. The truth is two files on expo/eas-cli@main: literal setEnv() calls in packages/worker/src/env.ts (cloud builds) and the env object in packages/local-build-plugin/src/build.ts (local builds). Manual sync has already failed twice: the files' own "keep in sync" comments point at the retired turtle-v2 repo, and the packages moved repos once (eas-build was archived into eas-cli), so the script fails loudly rather than reporting a clean run when a truth file vanishes. The deliverable is a local markdown report; this skill detects drift, it never edits docs.

The audited contract is EAS_BUILD* plus CI. Other vars the runners set (GRADLE_OPTS, LANG, MAESTRO_*) are infra tuning, out of scope by design.

Inputs

$ARGUMENTS is an optional path to a local expo/docs checkout. Default: ~/Documents/GitHub/expo/docs. If neither resolves, ask the user.

When NOT to use

• Env vars of other EAS surfaces (Workflows, Hosting). Different runners, different docs pages.
• Editing the docs page. Findings go in the report; a human applies them.
• Offline. The truth files are fetched from raw.githubusercontent.com.

Requirements

bun, network access to raw.githubusercontent.com, a local expo/docs checkout.

Step 1: Extract

bun <skill-dir>/scripts/extract.ts $ARGUMENTS

Line	Meaning	Your action
FATAL <why>	Truth file unreachable or page restructured	Stop. Locate the new definition site or collapsible first; never report a clean run.
UNDOCUMENTED <var> <runners>	Set by those runners, missing from the docs list	Finding. Check it isn't documented elsewhere (step 2).
STALE <var>	Documented, set by no runner	Finding: removal candidate.
CLOUD_ONLY <var> / LOCAL_ONLY <var>	Documented, but only one runner sets it	Finding: the list needs a per-runner caveat.
VALUE_MISMATCH <var> docs=<v> <runner>=<v>	Docs claim a literal value a runner contradicts	Finding.
EXPECTED <var> <reason>	Known intentional asymmetry	List under "known", no action.
COUNTS docs=N cloud=N local=N	Inventory sizes	Header sanity check; a sudden drop means extraction broke.

For each UNDOCUMENTED var, check whether another page already covers it:

grep -rn "<var>" <docs-repo>/pages --include='*.mdx'

A hit outside usage.mdx downgrades the finding to "documented elsewhere, consider cross-linking"; no hits anywhere means it is fully undocumented.

Step 2: Report

Write docs-eas-env-drift-<YYYY-MM-DD>.md in the current working directory:

1. Header: date, docs commit (git -C <docs-repo> rev-parse --short HEAD), the two truth file paths on expo/eas-cli@main, and the COUNTS line.
2. Findings: grouped by category, one plain sentence each, with the usage.mdx line number for vars already in the list (grep the collapsible) and the grep result for undocumented ones.
3. Known asymmetries: the EXPECTED lines, so readers don't re-report them.

Plain statements only, no rewritten doc text. The report is the only write; whether and how to fix the docs is the writer's call.