Hook Development for Claude Code Plugins
anthropics/claude-plugins-official
Explains how to write Claude Code plugin hooks, both prompt-based checks and bash commands, for events such as PreToolUse, Stop and SessionStart.
Full pipeline where an agent team collaborates to develop a CLI tool.
Install CLI Tool Builder
$ npx skills add revfactory/harness-100 --skill cli-tool-builder -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install revfactory/harness-100 cli-tool-builder --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/revfactory/harness-100.git skills-src && mkdir -p .claude/skills && cp -r skills-src/en/40-cli-tool-builder/.claude/skills/cli-tool-builder .claude/skills/cli-tool-builder && 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 "cli-tool-builder" agent skill from https://github.com/revfactory/harness-100/tree/main/en/40-cli-tool-builder/.claude/skills/cli-tool-builder into .claude/skills/cli-tool-builder/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "cli-tool-builder", 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/revfactory/harness-100/tree/main/en/40-cli-tool-builder/.claude/skills/cli-tool-builderType 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 revfactory/harness-100 --skill cli-tool-builder -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install revfactory/harness-100 cli-tool-builder --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/revfactory/harness-100.git skills-src && mkdir -p .agents/skills && cp -r skills-src/en/40-cli-tool-builder/.claude/skills/cli-tool-builder .agents/skills/cli-tool-builder && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "cli-tool-builder" agent skill from https://github.com/revfactory/harness-100/tree/main/en/40-cli-tool-builder/.claude/skills/cli-tool-builder into .agents/skills/cli-tool-builder/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "cli-tool-builder", 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 revfactory/harness-100 --skill cli-tool-builder -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install revfactory/harness-100 cli-tool-builder --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/revfactory/harness-100.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/en/40-cli-tool-builder/.claude/skills/cli-tool-builder .cursor/skills/cli-tool-builder && 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 "cli-tool-builder" agent skill from https://github.com/revfactory/harness-100/tree/main/en/40-cli-tool-builder/.claude/skills/cli-tool-builder into .cursor/skills/cli-tool-builder/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "cli-tool-builder", 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/revfactory/harness-100.git --path en/40-cli-tool-builder/.claude/skills/cli-tool-builder--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 revfactory/harness-100 --skill cli-tool-builder -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install revfactory/harness-100 cli-tool-builder --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/revfactory/harness-100.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/en/40-cli-tool-builder/.claude/skills/cli-tool-builder .gemini/skills/cli-tool-builder && 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 "cli-tool-builder" agent skill from https://github.com/revfactory/harness-100/tree/main/en/40-cli-tool-builder/.claude/skills/cli-tool-builder into .gemini/skills/cli-tool-builder/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "cli-tool-builder", 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 revfactory/harness-100 cli-tool-builderInstalls 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 revfactory/harness-100 --skill cli-tool-builder -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/revfactory/harness-100.git skills-src && mkdir -p .github/skills && cp -r skills-src/en/40-cli-tool-builder/.claude/skills/cli-tool-builder .github/skills/cli-tool-builder && 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 "cli-tool-builder" agent skill from https://github.com/revfactory/harness-100/tree/main/en/40-cli-tool-builder/.claude/skills/cli-tool-builder into .github/skills/cli-tool-builder/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "cli-tool-builder", 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 revfactory/harness-100 --skill cli-tool-builder -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install revfactory/harness-100 cli-tool-builder --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/revfactory/harness-100.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/en/40-cli-tool-builder/.claude/skills/cli-tool-builder .opencode/skills/cli-tool-builder && 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 "cli-tool-builder" agent skill from https://github.com/revfactory/harness-100/tree/main/en/40-cli-tool-builder/.claude/skills/cli-tool-builder into .opencode/skills/cli-tool-builder/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "cli-tool-builder", 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
cli-tool-builder- GitHub stars
- 1.3k
- Token cost
- ~1.6k tokens
- SKILL.md length
- 656 words
- Files
- 1
- Skills in repo
- 464
- Repo updated
- First seen
- Licence
- Apache-2.0
At a glance
Full pipeline where an agent team collaborates to develop a CLI tool.
- Works in 3 steps: Preparation (performed directly by the… → Team Assembly and Execution → Integration and Final Deliverables
- Requests like build me a CLI tool
- SKILL.md covers Execution Mode, Agent Composition, Workflow and Execution Modes by Request Scope, plus 4 more sections
- Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
What it does
CLI Tool Builder is an agent skill from revfactory/harness-100. Full pipeline where an agent team collaborates to develop a CLI tool. Use this skill for requests like 'build me a CLI tool', 'command-line tool development', 'CLI utility', 'terminal tool', 'command-line program', 'CLI app build', 'shell tool development', and other CLI tool development tasks. Also supports design-only mode when only command design is needed. Note: GUI app development, web dashboard construction, and IDE plugin development are outside the scope of this skill.
Its SKILL.md is about 1.6k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.
It sits in Agent Workflows, covering Hooks and plugins. The licence is Apache-2.0.
When your agent uses it
- Requests like build me a CLI tool
- Command-line tool development
- Command-line program
- Shell tool development
Example prompts
- “build me a CLI tool”
- “command-line tool development”
- “CLI utility”
- “/cli-tool-builder”
Requirements
- Python 3
- Node.js
Workflow steps
3 steps, taken from the step headings in SKILL.md.
What it can do on your machine
Read from SKILL.md and the folder at commit 8e8d35c. 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
No scripts in the folder and no shell commands in SKILL.md.
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
CLI Tool Builder loads about 1.6k tokens when it runs. Until then it costs about 125 tokens; SKILL.md has 656 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
The full file from revfactory/harness-100 at commit 8e8d35c, republished under its Apache-2.0 licence (© revfactory). 656 words, ~1,629 tokens.
Download SKILL.mdSave it as
.claude/skills/cli-tool-builder/SKILL.md (or your agent's skills folder).- name
- cli-tool-builder
- description
- Full pipeline where an agent team collaborates to develop a CLI tool. Use this skill for requests like 'build me a CLI tool', 'command-line tool development', 'CLI utility', 'terminal tool', 'command-line program', 'CLI app build', 'shell tool development', and other CLI tool development tasks. Also supports design-only mode when only command design is needed. Note: GUI app development, web dashboard construction, and IDE plugin development are outside the scope of this skill.
CLI Tool Builder — CLI Tool Development Pipeline
An agent team collaborates to develop CLI tools through command design > parser implementation > handlers > testing > documentation > deployment.
Execution Mode
Agent Team — Five agents communicate directly via SendMessage and perform cross-validation.
Agent Composition
| Agent | File | Role | Type |
|---|---|---|---|
| command-designer | .claude/agents/command-designer.md | Command structure design | general-purpose |
| core-developer | .claude/agents/core-developer.md | Core implementation | general-purpose |
| test-engineer | .claude/agents/test-engineer.md | Test writing | general-purpose |
| docs-writer | .claude/agents/docs-writer.md | Documentation writing | general-purpose |
| release-engineer | .claude/agents/release-engineer.md | Build, deployment | general-purpose |
Workflow
Phase 1: Preparation (performed directly by the orchestrator)
- Extract the following from user input:
- Tool purpose: What the CLI does
- Language/Runtime: Python/Node.js/Go/Rust (default: Python)
- Key features: List of core subcommands
- Distribution channel: PyPI/npm/Homebrew/binary
- Constraints (optional): Dependency limitations, compatible OS, performance requirements
- Create the
_workspace/directory at the project root - Organize the input and save it to
_workspace/00_input.md - Create the
_workspace/src/directory - If pre-existing files are available, copy them to
_workspace/and skip the corresponding phase - Determine the execution mode based on the scope of the request
Phase 2: Team Assembly and Execution
| Order | Task | Owner | Dependencies | Deliverable |
|---|---|---|---|---|
| 1 | Command structure design | designer | None | _workspace/01_command_design.md |
| 2 | Core implementation | developer | Task 1 | _workspace/02_core_implementation.md + src/ |
| 3a | Test writing | tester | Task 2 | _workspace/03_test_suite.md + src/tests/ |
| 3b | Documentation | docs | Tasks 1, 2 | _workspace/04_documentation.md |
| 4 | Release configuration | release | Tasks 2, 3a | _workspace/05_release_config.md + CI files |
Tasks 3a (testing) and 3b (documentation) run in parallel.
Inter-agent communication flow:
- designer completes > passes command schema to developer, passes --help drafts to docs
- developer completes > passes mock points to tester, passes API to docs, passes build info to release
- tester completes > passes bug reports to developer (if any), passes CI test config to release
- docs completes > passes README path to release
- release integrates all deliverables to complete the deployment pipeline
Phase 3: Integration and Final Deliverables
- Verify that the code in
_workspace/src/is executable - Verify that tests pass
- Validate consistency between documentation and code
- Report the final summary to the user
Execution Modes by Request Scope
| User Request Pattern | Execution Mode | Agents Deployed |
|---|---|---|
| "Build me a CLI tool", "full development" | Full pipeline | All 5 agents |
| "Just design the command structure" | Design mode | designer only |
| "Add a subcommand to this CLI" | Extension mode | designer + developer + tester |
| "Write tests for this CLI" | Test mode | tester only |
| "Just set up deployment" | Deploy mode | release only |
Data Transfer Protocol
| Strategy | Method | Purpose |
|---|---|---|
| File-based | _workspace/ directory | Design documents and configuration sharing |
| Message-based | SendMessage | Real-time key information transfer, bug reports |
| Code-based | _workspace/src/ | Executable source code |
Show full SKILL.md (249 more words)Show less
Error Handling
| Error Type | Strategy |
|---|---|
| Tool purpose unclear | Research similar CLI tools via WebSearch, propose 3 candidates |
| Language not specified | Default to Python (typer), state reasoning and alternatives |
| Test failure | Send bug report to developer, retest after fix (up to 2 rounds) |
| Cross-platform build failure | Switch affected OS build to CI-only, present local build alternatives |
| Agent failure | Retry once > if still failing, proceed without that deliverable |
Test Scenarios
Normal Flow
Prompt: "Build a file conversion CLI tool in Python. Support JSON/YAML/TOML conversion" Expected result:
- Command design:
convert [input] --from json --to yaml --output out.yaml - Core: typer-based, parser + conversion logic + output formatter
- Testing: Each conversion combination, invalid format input, pipe input
- Documentation: README + installation + quick start + full command reference
- Release: pyproject.toml + GitHub Actions CI + PyPI deployment
Existing File Reuse Flow
Prompt: "Just add tests and docs to this CLI code" + CLI source code attached Expected result:
- Copy existing source code to
_workspace/src/ - Skip designer and developer; deploy tester + docs + release
- Analyze existing code's command structure to generate tests and documentation
Error Flow
Prompt: "Build me a CLI" (purpose unclear) Expected result:
- designer requests tool purpose clarification from user
- Present 3 examples of similar popular CLI tools
- Proceed with remaining pipeline after purpose is confirmed
Agent Extension Skills
Extension skills that enhance agent domain expertise:
| Skill | File | Target Agent | Role |
|---|---|---|---|
| arg-parser-generator | .claude/skills/arg-parser-generator/skill.md | command-designer, core-developer | Argument type classification, subcommand patterns, per-language parser boilerplate, help text standard |
| ux-linter | .claude/skills/ux-linter/skill.md | test-engineer, docs-writer | CLI UX 12 principles, error message standards, output format guide, color/interaction patterns |
© revfactory, Apache-2.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
Just SKILL.md in en/40-cli-tool-builder/.claude/skills/cli-tool-builder of revfactory/harness-100.
Open the folder on GitHubat commit 8e8d35c
Compare with similar skills
CLI Tool Builder 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 |
|---|---|---|---|---|---|---|
| CLI Tool Builder this skillrevfactory/harness-100 | 1.3k | — | ~1.6k | Automated safety check: Pass | Apache-2.0 | |
| Hook Development for Claude Code Pluginsanthropics/claude-plugins-official | 37k | 11 repos | ~4.1k | Automated safety check: Notes | Apache-2.0 | |
| Claude Code Agent Developmentanthropics/claude-plugins-official | 37k | 8 repos | ~2.8k | Automated safety check: Pass | Apache-2.0 | |
| Claude Code Skill Developer Guidediet103/claude-code-infrastructure-showcase | 10k | 10 repos | ~3.5k | Automated safety check: Pass | MIT | |
| Plugin Settings Patternanthropics/claude-plugins-official | 37k | 7 repos | ~3k | Automated safety check: Pass | Apache-2.0 | |
| MCP Integration for Pluginsanthropics/claude-plugins-official | 37k | 11 repos | ~3.1k | Automated safety check: Pass | Apache-2.0 |
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Related
Categories
Questions about CLI Tool Builder
What does CLI Tool Builder do?
Full pipeline where an agent team collaborates to develop a CLI tool. CLI Tool Builder is an agent skill from revfactory/harness-100. Full pipeline where an agent team collaborates to develop a CLI tool.
When should I use CLI Tool Builder?
CLI Tool Builder fits situations like: requests like build me a CLI tool; command-line tool development; command-line program; shell tool development.
How do I install CLI Tool Builder in Claude Code?
Run `npx skills add revfactory/harness-100 --skill cli-tool-builder -a claude-code`. Or copy the skill folder (en/40-cli-tool-builder/.claude/skills/cli-tool-builder in revfactory/harness-100) into .claude/skills/cli-tool-builder in your project. Claude Code loads it when a task matches its description.
How do I install CLI Tool Builder in Codex?
Run `npx skills add revfactory/harness-100 --skill cli-tool-builder -a codex`. Or copy the skill folder (en/40-cli-tool-builder/.claude/skills/cli-tool-builder in revfactory/harness-100) into .agents/skills/cli-tool-builder in your project. Codex loads it when a task matches its description.
Can I use CLI Tool Builder 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 revfactory/harness-100 --skill cli-tool-builder -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/cli-tool-builder, .gemini/skills/cli-tool-builder, .github/skills/cli-tool-builder and .opencode/skills/cli-tool-builder in your project.
What does CLI Tool Builder need to run?
SKILL.md names no scripts, command-line tools or credentials: CLI Tool Builder is instructions for the agent only. Our summary lists: Python 3; Node.js.
Does CLI Tool Builder 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 CLI Tool Builder 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 CLI Tool Builder use?
CLI Tool Builder is published under the Apache-2.0 licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does CLI Tool Builder use?
About 1.6k tokens (SKILL.md is roughly 6.5k 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 CLI Tool Builder?
Skills that share tags, products or a category with CLI Tool Builder: Hook Development for Claude Code Plugins (anthropics/claude-plugins-official, 37k stars), Claude Code Agent Development (anthropics/claude-plugins-official, 37k stars), Claude Code Skill Developer Guide (diet103/claude-code-infrastructure-showcase, 10k stars) and Plugin Settings Pattern (anthropics/claude-plugins-official, 37k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains CLI Tool Builder?
revfactory (a GitHub user) maintains it in revfactory/harness-100, which has 1,290 GitHub stars. The repository holds 464 skills in this directory. The repository was last updated on March 22, 2026.
Source: revfactory/harness-100 on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.