# Biome Foundation

> Use when building linters/formatters/language tooling: lossless CSTs with green/red splits, flat formatter IRs with best-fitting printing, rule engines with lazy diagnostics and positional suppressions, and event-stream parser drivers with buffered lookahead, speculative disambiguation, and marker-surgery recovery.

- Skill: `ryan-brosas/biome-foundation` (Agent Skill, multi-file: 204 files)
- Install (CLI): `npx skillmds@latest add ryan-brosas/biome-foundation`
- Raw SKILL.md: https://api.skillmd.com/api/skills/ryan-brosas/biome-foundation/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: ryan-brosas (https://skillmd.com/u/ryan-brosas)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/ryan-brosas/biome-foundation

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# Biome Foundation

## Foundation contract

This is a cold, source-specific foundation, not an operational procedure. It is
historical, revision-pinned evidence rather than timeless guidance. Current
project source, tests, requirements, and runtime behavior outrank this
projection and decide what ships.

## Provenance and revision

- Source record: `biome`; portable upstream identity, license, coverage caveats, and retrieval history are preserved in the index.
- Recorded revision: `main@6cd32636f463551b8dfe46aeefb1191d437b4694`.
- Full provenance, coverage caveats, boundaries, and preserved evidence:
  `references/index.md`.

## Topic map

- Representative topics: Lossless CST; Rowan cache/cursor layer; JS grammar
  planes (pass 3); Formatter IR; Printer decision machinery; Rule engine;
  Parser driver; Buffered lexer.
- Scope and retrieval questions: `references/index.md#use-this-for`.
- Complete capsule chooser: `references/index.md#load-the-matching-source-dump`.
- Detailed grouped map: `references/index.md#capsule-map`.
- Source limitations and portability boundaries: `references/index.md#boundaries`.

## Retrieval

Open the index, choose one capsule matching the active question, and load only
that capsule. Revalidate its cited source and revision before relying on it. Do
not bulk-load the inventory, treat historical claims as current truth, or apply
this foundation as a procedure.