Claude Code Plugin Structure
anthropics/claude-plugins-official
Explains the directory layout, plugin.json manifest and component organization of a Claude Code plugin, including auto-discovery and portable paths.
Explains how the Crush coding agent embeds builtin skills in its binary and how to add or edit one, including the discovery test and build commands.
Install Crush Builtin Skills
$ npx skills add charmbracelet/crush --skill builtin-skills -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install charmbracelet/crush builtin-skills --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/charmbracelet/crush.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.agents/skills/builtin-skills .claude/skills/builtin-skills && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "builtin-skills" agent skill from https://github.com/charmbracelet/crush/tree/main/.agents/skills/builtin-skills into .claude/skills/builtin-skills/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "builtin-skills", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/charmbracelet/crush/tree/main/.agents/skills/builtin-skillsType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add charmbracelet/crush --skill builtin-skills -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install charmbracelet/crush builtin-skills --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/charmbracelet/crush.git skills-src && mkdir -p .agents/skills && cp -r skills-src/.agents/skills/builtin-skills .agents/skills/builtin-skills && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "builtin-skills" agent skill from https://github.com/charmbracelet/crush/tree/main/.agents/skills/builtin-skills into .agents/skills/builtin-skills/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "builtin-skills", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add charmbracelet/crush --skill builtin-skills -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install charmbracelet/crush builtin-skills --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/charmbracelet/crush.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/.agents/skills/builtin-skills .cursor/skills/builtin-skills && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "builtin-skills" agent skill from https://github.com/charmbracelet/crush/tree/main/.agents/skills/builtin-skills into .cursor/skills/builtin-skills/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "builtin-skills", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/charmbracelet/crush.git --path .agents/skills/builtin-skills--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add charmbracelet/crush --skill builtin-skills -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install charmbracelet/crush builtin-skills --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/charmbracelet/crush.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/.agents/skills/builtin-skills .gemini/skills/builtin-skills && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "builtin-skills" agent skill from https://github.com/charmbracelet/crush/tree/main/.agents/skills/builtin-skills into .gemini/skills/builtin-skills/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "builtin-skills", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install charmbracelet/crush builtin-skillsInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add charmbracelet/crush --skill builtin-skills -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/charmbracelet/crush.git skills-src && mkdir -p .github/skills && cp -r skills-src/.agents/skills/builtin-skills .github/skills/builtin-skills && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "builtin-skills" agent skill from https://github.com/charmbracelet/crush/tree/main/.agents/skills/builtin-skills into .github/skills/builtin-skills/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "builtin-skills", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add charmbracelet/crush --skill builtin-skills -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install charmbracelet/crush builtin-skills --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/charmbracelet/crush.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/.agents/skills/builtin-skills .opencode/skills/builtin-skills && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "builtin-skills" agent skill from https://github.com/charmbracelet/crush/tree/main/.agents/skills/builtin-skills into .opencode/skills/builtin-skills/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "builtin-skills", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
builtin-skills- GitHub stars
- 29k
- Token cost
- ~466 tokens
- SKILL.md length
- 162 words
- Files
- 1
- Skills in repo
- 5
- Repo updated
- First seen
- Licence
- Custom licence
At a glance
Explains how the Crush coding agent embeds builtin skills in its binary and how to add or edit one, including the discovery test and build commands.
- Works in 4 steps: Create internal/skills/builtin//SKILL.md… → No extra wiring needed — //go:embed… → Add a test assertion in… → …
- Creating a new builtin skill for Crush
- SKILL.md covers How It Works, Adding a New Builtin Skill and Existing Builtin Skills
- Calls go
What it does
Crush ships some skills inside its binary from internal/skills/builtin, so they are always available without user setup. Each lives in its own folder with a SKILL.md, the tree is embedded at compile time, DiscoverBuiltin parses each file and gives it a crush://skills/ path, and the View tool reads those paths from the embedded files rather than from disk. A user skill with the same name overrides a builtin.
To add one, create a folder whose name matches the name field in the YAML frontmatter, write the instructions in markdown, and add an assertion to TestDiscoverBuiltin in internal/skills/skills_test.go; no extra wiring is needed. Then run go build and the internal/skills tests. The page lists the current builtins: crush-config for configuration help, crush-hooks for writing and debugging hooks, and jq for using the jq JSON processor.
When your agent uses it
- Creating a new builtin skill for Crush
- Editing an existing skill under internal/skills/builtin
- Understanding how embedded skills are discovered and overridden
Example prompts
- “Add a builtin skill to Crush that explains how to use ripgrep, including the test assertion.”
- “How does a user skill override a builtin one in Crush?”
Requirements
- A checkout of the Crush repository
- A Go toolchain
Workflow steps
4 steps, taken from the first numbered list in SKILL.md.
- Create internal/skills/builtin//SKILL.md with YAML frontmatter
- No extra wiring needed — //go:embed builtin/* picks up new directories
- Add a test assertion in TestDiscoverBuiltin in
- Build and test: go build . && go test ./internal/skills/...
What it can do on your machine
Read from SKILL.md and the folder at commit df5b024. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
Shell commands in SKILL.md call:
go
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Crush Builtin Skills loads about 466 tokens when it runs. Until then it costs about 50 tokens; SKILL.md has 162 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
SKILL.md
Its licence (Custom licence) doesn't allow us to republish the file, so here is its outline and opening line. It has 162 words (~466 tokens).
“Crush embeds skills directly into the binary via internal/skills/builtin/. These are always available without user configuration.”
- name
- builtin-skills
Files
Just SKILL.md in .agents/skills/builtin-skills of charmbracelet/crush.
Open the folder on GitHubat commit df5b024
Compare with similar skills
Crush Builtin Skills next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Crush Builtin Skills this skillcharmbracelet/crush | 29k | — | ~466 | Automated safety check: Pass | Custom licence | |
| Claude Code Plugin Structureanthropics/claude-plugins-official | 38k | 10 repos | ~3.4k | Automated safety check: Pass | Apache-2.0 | |
| SkillAnything Skill GeneratorAgentSkillOS/SkillAnything | 471 | — | ~1.9k | Automated safety check: Pass | MIT | |
| LubanLearnPrompt/luban-skill | 959 | — | ~3.1k | Automated safety check: Pass | MIT | |
| Build Cs Skillcodestable/CodeStable | 1.1k | — | ~3k | Automated safety check: Pass | None | |
| ShellLM Skill Authorlaude-institute/headlong | 1.2k | — | ~1.3k | Automated safety check: Pass | Apache-2.0 |
Similar skills
- Official
SkillAnything Skill Generator
AgentSkillOS/SkillAnything
Generates a complete agent skill for a target tool, API, library or workflow through a seven-phase pipeline that ends with testing, tuning and packaging for several platforms.
Luban
LearnPrompt/luban-skill
鲁班（Luban）——Skill打磨工坊。把一个"能用的Skill"打磨成"能被理解、能被安装、能被传播、能被验证、能持续进化"的公共Skill资产。
Build Cs Skill
codestable/CodeStable
CodeStable skill authoring and evolution protocol. An agent skill from codestable/CodeStable.
ShellLM Skill Author
laude-institute/headlong
Scaffolds new ShellLM skills with the right frontmatter, directory layout and agent-facing writing style, so an agent can extend its own capabilities.
AIDD Skill Authoring Guide
paralleldrive/aidd
Guides creating, reviewing or refactoring AI-Driven Development skills so each one stays minimal, composable and named around a single clear function.
More from charmbracelet/crush
Crush Configuration
charmbracelet/crush
Explains how to configure the Crush coding agent with crushrc or crush.json, covering providers, models, LSPs, MCP servers, hooks, permissions and config precedence.
Crush Hook Writer
charmbracelet/crush
Helps write, debug and configure Crush hooks in crush.json that block, approve or rewrite tool calls before they run.
JSON Processing with jq
charmbracelet/crush
Explains the jq command built into Crush for querying, filtering and reshaping JSON, including its supported flags and where it differs from standard jq.
Crush Shell Builtins
charmbracelet/crush
Explains how to add a new in-process builtin command to Crush's embedded POSIX shell, so it is intercepted before reaching the OS, with context polling and exit-status rules.
Related
Categories
Questions about Crush Builtin Skills
What does Crush Builtin Skills do?
Explains how the Crush coding agent embeds builtin skills in its binary and how to add or edit one, including the discovery test and build commands. Crush ships some skills inside its binary from internal/skills/builtin, so they are always available without user setup.md, the tree is embedded at compile time, DiscoverBuiltin parses each file and gives it a crush://skills/ path, and the View tool reads those paths from the embedded files rather than from disk.
When should I use Crush Builtin Skills?
Crush Builtin Skills fits situations like: creating a new builtin skill for Crush; editing an existing skill under internal/skills/builtin; understanding how embedded skills are discovered and overridden.
How do I install Crush Builtin Skills in Claude Code?
Run `npx skills add charmbracelet/crush --skill builtin-skills -a claude-code`. Or copy the skill folder (.agents/skills/builtin-skills in charmbracelet/crush) into .claude/skills/builtin-skills in your project. Claude Code loads it when a task matches its description.
How do I install Crush Builtin Skills in Codex?
Run `npx skills add charmbracelet/crush --skill builtin-skills -a codex`. Or copy the skill folder (.agents/skills/builtin-skills in charmbracelet/crush) into .agents/skills/builtin-skills in your project. Codex loads it when a task matches its description.
Can I use Crush Builtin Skills in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add charmbracelet/crush --skill builtin-skills -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/builtin-skills, .gemini/skills/builtin-skills, .github/skills/builtin-skills and .opencode/skills/builtin-skills in your project.
What does Crush Builtin Skills need to run?
Going by SKILL.md and its folder, Crush Builtin Skills needs the command-line tools its instructions call (go). Our summary lists: A checkout of the Crush repository; A Go toolchain.
Does Crush Builtin Skills access the network?
SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.
Is Crush Builtin Skills safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does Crush Builtin Skills use?
Crush Builtin Skills has a licence file (the repository's licence) that doesn't match a standard licence. Read it on GitHub before reusing the skill.
How many tokens does Crush Builtin Skills use?
About 466 tokens (SKILL.md is roughly 1.9k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.
What are the alternatives to Crush Builtin Skills?
Skills that share tags, products or a category with Crush Builtin Skills: Claude Code Plugin Structure (anthropics/claude-plugins-official, 38k stars), SkillAnything Skill Generator (AgentSkillOS/SkillAnything, 471 stars), Luban (LearnPrompt/luban-skill, 959 stars) and Build Cs Skill (codestable/CodeStable, 1.1k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Crush Builtin Skills?
charmbracelet (a GitHub organization) maintains it in charmbracelet/crush, which has 28,591 GitHub stars. The repository holds 5 skills in this directory. The repository was last updated on October 11, 2026.
Source: charmbracelet/crush on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.