e18e-skill #

Ecosystem-performance fluency for AI coding agents. 1 skill, 4 commands, runtime-verified against the live e18e module-replacements manifest.

Why #

AI coding agents tend to default to whatever was common in their training data: axios over fetch, moment over day.js, lodash over native, polyfills for APIs the runtime now has. The e18e initiative coordinates community work to fix this across the JavaScript ecosystem — one package at a time — through three pillars: cleanup, speedup, levelup.

This project gives AI harnesses the same vocabulary and the same rules: measure before and after, respect the Node floor and module-format contract, upstream first, one package per PR.

What's Included #

The Skill: /e18e #

A context-first skill that gathers project info (Node floor, module format, bundler, consumer constraints) into .e18e.md. Every command reads that context before doing anything else.

Reference files (source/skills/e18e/reference/):

Reference	Covers
cleanup	Remove redundant deps; discover/classify/measure/ship
speedup	Profile hot paths; the rule: always measure
levelup	Replace old-generation deps with ESM-first, typed, tree-shakeable successors
module-replacements	Curated original → replacement table (static snapshot)
native-replacements	module → native API mappings gated by Node floor (static snapshot)
tooling	@e18e/cli, @e18e/eslint-plugin, publint, attw, tinybench, and the rest
contributing	Upstream contribution workflow via e18e/ecosystem-issues

4 Commands (one per pillar, plus audit) #

Command	Modes	What it does
/audit	/audit, /audit <area>, /audit graph <dep>	Scored report across 5 dimensions, P0-P3 findings, no edits
/cleanup	/cleanup, /cleanup <dep>, /cleanup size, /cleanup native, /cleanup graph <dep>	Remove, swap, or inline deps; reduce tarball/bundle/install size
/speedup	/speedup, /speedup <target>, /speedup bench <name>	Profile + fix runtime perf; scaffold benchmarks; always measured
/levelup	/levelup, /levelup <dep>, /levelup modernize, /levelup publint	Modernize deps; apply ESLint modernization; validate publish shape

Typical flows #

/e18e teach                       # one-time: gather project context
/e18e scan                        # cheap first-look overview
/audit                            # scored report
/cleanup                          # start removing bloat (one dep at a time)
/cleanup moment                   # targeted swap of one dep
/cleanup native                   # sweep for polyfills at the Node floor
/speedup src/parser.ts            # profile + fix a known hot path
/levelup publint                  # before a library release

Runtime manifest verification #

Static reference tables drift as the ecosystem moves. For recommendations that involve a specific dep swap, the skills use WebFetch against the live e18e manifests before recommending:

• manifests/native.json — module → native API
• manifests/preferred.json — module → preferred module
• manifests/micro-utilities.json — module → inline expression

If WebFetch is unavailable the skills fall back to the static reference snapshot and tell the user the recommendation is from cached data. This keeps day-to-day use fast while ensuring recommendations for the volatile parts stay current.

Principles #

Every command inherits the same non-negotiables:

• One package at a time. Each change is a reviewable, revertible PR.
• Profile before and after. No unmeasured performance claims.
• Measure install/bundle size deltas for any cleanup or levelup.
• Respect the Node floor and module-format contract. engines.node and exports shape are contracts.
• Upstream first, local workaround second. overrides/resolutions are a last resort.
• Prefer native > focused module > multi-tool replacement > keep. In that order when all are viable.

Installation #

Claude Code (project-specific):

cp -r .claude/skills/* your-project/.claude/skills/

Claude Code (global):

cp -r .claude/skills/* ~/.claude/skills/

Run /e18e teach once in a project to populate .e18e.md with your project's runtime and publish-shape context. Every other command uses it.

Build #

Skills are authored in source/skills/ and copied to .claude/skills/ by:

node scripts/build.mjs

No templating, no preprocessing — .claude/skills/ is a mirror of source/skills/ after build.

Contributing #

Patterns, replacements, and tooling move fast in this ecosystem. PRs that update the static reference files against the current state of the upstream e18e manifests are welcome. One change per PR.

License #

Beerware. See LICENSE.

Not officially affiliated with e18e.