opencode-expertiselisted

# opencode Expertise opencode is a self-hostable AI coding agent (Bun/TypeScript backend). It is **highly extensible but TypeScript-restrictive**: content surfaces are declarative (markdown/JSON), but every *programmatic* surface — plugins, custom tools, and therefore anything hook-shaped — must be written in TypeScript/JavaScript running on Bun. Facts marked ✅ were verified against https://opencode.ai/docs and the published `@opencode-ai/plugin` 1.18.29 type declarations on 2026-09-06. Unmarked details come from gathered notes and may be stale or specific to a private fork — re-verify before relying on them. opencode moves fast; when a path 404s or a field is rejected, check the docs before assuming a bug. ## Extension-surface map | Surface | Project location | Global location | Format | TS required? | |---|---|---|---|---| | Config ✅ | `opencode.json{,c}` (root; found by walking up to the nearest git dir). `.opencode/opencode.json{,c}` as a config *file* is unverified — the docs list `.opencode/` as a directory level for agents/commands/plugins | `~/.config/opencode/opencode.json{,c}` | JSON/JSONC | No | | Rules ✅ | `AGENTS.md` (walks up; `CLAUDE.md` fallback) | `~/.config/opencode/AGENTS.md` (`~/.claude/CLAUDE.md` fallback) | Markdown | No | | Agents ✅ | `.opencode/agents/*.md` | `~/.config/opencode/agents/*.md` | Markdown + frontmatter | No | | Skills ✅ | `.opencode/skills/<name>/SKILL.md` (also reads `.claude/skills/`, `.agents/skills/`) | `~/.config/opencode/skills/