Agent skill

Add Tool

by AlphaLab-USTC in AlphaLab-USTC/OhMyCode

Guide for adding a new tool to OhMyCode. An agent skill from AlphaLab-USTC/OhMyCode.

MITAuto-check passedTesting & QA

Install Add Tool

skills CLI

$ npx skills add AlphaLab-USTC/OhMyCode --skill add-tool -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI

$ gh skill install AlphaLab-USTC/OhMyCode add-tool --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy

$ git clone --depth 1 https://github.com/AlphaLab-USTC/OhMyCode.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.agents/skills/add-tool .claude/skills/add-tool && rm -rf skills-src

Use ~/.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/

Paste into Claude Code

Install the "add-tool" agent skill from https://github.com/AlphaLab-USTC/OhMyCode/tree/main/.agents/skills/add-tool into .claude/skills/add-tool/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "add-tool", 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

$skill-installer install https://github.com/AlphaLab-USTC/OhMyCode/tree/main/.agents/skills/add-tool

Type 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.

skills CLI

$ npx skills add AlphaLab-USTC/OhMyCode --skill add-tool -a codex

Project install goes to .agents/skills/; add -g for ~/.codex/skills/.

GitHub CLI

$ gh skill install AlphaLab-USTC/OhMyCode add-tool --agent codex

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/AlphaLab-USTC/OhMyCode.git skills-src && mkdir -p .agents/skills && cp -r skills-src/.agents/skills/add-tool .agents/skills/add-tool && rm -rf skills-src

Use ~/.agents/skills/ instead of .agents/skills for a personal install.

Codex skills documentation · loads skills from .agents/skills/

Paste into Codex

Install the "add-tool" agent skill from https://github.com/AlphaLab-USTC/OhMyCode/tree/main/.agents/skills/add-tool into .agents/skills/add-tool/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "add-tool", 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.

skills CLI

$ npx skills add AlphaLab-USTC/OhMyCode --skill add-tool -a cursor

Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.

GitHub CLI

$ gh skill install AlphaLab-USTC/OhMyCode add-tool --agent cursor

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/AlphaLab-USTC/OhMyCode.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/.agents/skills/add-tool .cursor/skills/add-tool && rm -rf skills-src

Use ~/.cursor/skills/ instead of .cursor/skills for a personal install.

Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/

Paste into Cursor

Install the "add-tool" agent skill from https://github.com/AlphaLab-USTC/OhMyCode/tree/main/.agents/skills/add-tool into .cursor/skills/add-tool/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "add-tool", 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

$ gemini skills install https://github.com/AlphaLab-USTC/OhMyCode.git --path .agents/skills/add-tool

--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.

skills CLI

$ npx skills add AlphaLab-USTC/OhMyCode --skill add-tool -a gemini-cli

Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.

GitHub CLI

$ gh skill install AlphaLab-USTC/OhMyCode add-tool --agent gemini-cli

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/AlphaLab-USTC/OhMyCode.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/.agents/skills/add-tool .gemini/skills/add-tool && rm -rf skills-src

Use ~/.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/

Paste into Gemini CLI

Install the "add-tool" agent skill from https://github.com/AlphaLab-USTC/OhMyCode/tree/main/.agents/skills/add-tool into .gemini/skills/add-tool/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "add-tool", 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.

GitHub CLI

$ gh skill install AlphaLab-USTC/OhMyCode add-tool

Installs 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).

skills CLI

$ npx skills add AlphaLab-USTC/OhMyCode --skill add-tool -a github-copilot

Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.

Manual copy

$ git clone --depth 1 https://github.com/AlphaLab-USTC/OhMyCode.git skills-src && mkdir -p .github/skills && cp -r skills-src/.agents/skills/add-tool .github/skills/add-tool && rm -rf skills-src

Use ~/.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/

Paste into GitHub Copilot

Install the "add-tool" agent skill from https://github.com/AlphaLab-USTC/OhMyCode/tree/main/.agents/skills/add-tool into .github/skills/add-tool/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "add-tool", 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.

skills CLI

$ npx skills add AlphaLab-USTC/OhMyCode --skill add-tool -a opencode

OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.

GitHub CLI

$ gh skill install AlphaLab-USTC/OhMyCode add-tool --agent opencode

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/AlphaLab-USTC/OhMyCode.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/.agents/skills/add-tool .opencode/skills/add-tool && rm -rf skills-src

Use ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.

OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/

Paste into OpenCode

Install the "add-tool" agent skill from https://github.com/AlphaLab-USTC/OhMyCode/tree/main/.agents/skills/add-tool into .opencode/skills/add-tool/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "add-tool", 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: add-tool
GitHub stars: 131
Token cost: ~758 tokens
SKILL.md length: 271 words
Files: 2
Skills in repo: 10
Repo updated: Apr 2, 2026
First seen: Oct 7, 2026
Licence: MIT

At a glance

Guide for adding a new tool to OhMyCode. An agent skill from AlphaLab-USTC/OhMyCode.

Works in 6 steps: Define the Tool → Create the Tool File → Write Tests (TDD) → …
User wants to create a custom tool
SKILL.md covers When to Use, Prerequisites, Step-by-Step Guide and Key Requirements, plus 1 more section
Runs Python scripts from its folder; calls python3 and git

What it does

Add Tool is an agent skill from AlphaLab-USTC/OhMyCode. Guide for adding a new tool to OhMyCode. Use when user wants to create a custom tool.

Its SKILL.md is about 760 tokens, which your agent loads only when the skill is triggered. The skill folder holds 2 other files (for example `templates/tool_template.py`).

It sits in Testing & QA. The repository describes itself as: Minimal and Customizable CC-Style Coding Agent. The licence is MIT.

When your agent uses it

User wants to create a custom tool

Example prompts

“/add-tool”

Requirements

Python 3

Workflow steps

6 steps, taken from the step headings in SKILL.md.

Define the Tool
Create the Tool File
Write Tests (TDD)
Verify
Test End-to-End
Commit

What it can do on your machine

Read from SKILL.md and the folder at commit 4d1bb28. 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
Ships script files (Python), which the agent can run.
Shell commands in SKILL.md call:
- python3
- git
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md. Its commands use git, which can reach the network depending on how they are called.
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

Add Tool loads about 758 tokens when it runs. Until then it costs about 24 tokens; SKILL.md has 271 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~24
When it runs · the whole SKILL.md, loaded when a task matches: ~758

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 AlphaLab-USTC/OhMyCode at commit 4d1bb28, republished under its MIT licence (© AlphaLab-USTC). 271 words, ~758 tokens.

Download SKILL.mdSave it as .claude/skills/add-tool/SKILL.md (or your agent's skills folder). This skill also uses 1 other file; get the full folder from GitHub.

name: add-tool
description: Guide for adding a new tool to OhMyCode. Use when user wants to create a custom tool.

Add a New Tool to OhMyCode

Create a new tool that the AI assistant can use during conversations.

When to Use

User says "add a tool", "create a tool", "I want a new tool"
User describes a capability they want the AI to have (e.g., "I want it to run SQL queries")

Prerequisites

Read docs/DEVELOPMENT_GUIDE.md for project conventions
Read ohmycode/tools/base.py to understand Tool, ToolContext, ToolResult, @register_tool
Look at an existing tool (e.g., ohmycode/tools/bash.py) as reference

Step-by-Step Guide

Step 1: Define the Tool

Ask the user:

Tool name — short, lowercase, snake_case (e.g., sql_query, docker_run)
Description — one sentence for the LLM to understand when to use it
Parameters — what inputs does it need? (JSON Schema format)
Concurrent safety — can it run in parallel with other tools? (True for read-only, False for side effects)

Step 2: Create the Tool File

Copy the template from templates/tool_template.py to ohmycode/tools/<tool_name>.py.

Fill in:

name, description, parameters, concurrent_safe class attributes
execute() method with the actual logic

Step 3: Write Tests (TDD)

Create tests/tools/test_<tool_name>.py:

python

import pytest
from ohmycode.tools.base import ToolContext
from ohmycode.tools.<tool_name> import <ToolClass>

@pytest.fixture
def ctx(tmp_path):
    return ToolContext(mode="auto", agent_depth=0, cwd=str(tmp_path), is_sub_agent=False)

@pytest.mark.asyncio
async def test_<tool_name>_basic(ctx):
    tool = <ToolClass>()
    result = await tool.execute({"param": "value"}, ctx)
    assert not result.is_error
    assert "expected" in result.output

Step 4: Verify

bash

python3 -m pytest tests/tools/test_<tool_name>.py -v   # New tests pass
python3 -m pytest tests/ -v                              # No regressions

Step 5: Test End-to-End

bash

ohmycode -p "Use the <tool_name> tool to ..." --mode auto

Step 6: Commit

bash

git add ohmycode/tools/<tool_name>.py tests/tools/test_<tool_name>.py
git commit -m "feat(tools): add <tool_name> tool"

Key Requirements

Tool file goes in ohmycode/tools/ — auto-imported, no other files need to change
Use @register_tool decorator on the class
execute() must be async and return ToolResult
Never raise exceptions from execute() — return ToolResult(is_error=True) instead
Keep the file under 150 lines
Parameters must be valid JSON Schema

Common Mistakes

Forgetting @register_tool decorator → tool won't be available
Raising exceptions instead of returning ToolResult(is_error=True) → crashes the loop
Using concurrent_safe = True on tools with side effects → race conditions
Not handling missing optional parameters → KeyError at runtime
File name collision with existing tools → check ohmycode/tools/ first

Files

SKILL.md and 1 other file in .agents/skills/add-tool of AlphaLab-USTC/OhMyCode.

SKILL.md
templates/tool_template.py

Open the folder on GitHubat commit 4d1bb28

Compare with similar skills

Add Tool 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.

Add Tool compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
Add Tool this skillAlphaLab-USTC/OhMyCode	131	—	~758	Automated safety check: Pass	MIT	6 mo ago
Web Application Testinganthropics/skills	180k	51 repos	~966	Automated safety check: Pass	Apache-2.0	today
Diagnosing Bugsfossasia/eventyay-interpretation	1.6k	32 repos	~2.1k	Automated safety check: Pass	Apache-2.0	3 days ago
TDDpietheinstrengholt/rssmonster	564	30 repos	~906	Automated safety check: Pass	MIT	yesterday
TDD WorkflowhellangleZ/burn-in-cceverywhere-ralph	112	11 repos	~2.4k	Automated safety check: Pass	None	8 mo ago
TDDsanity-io/sanity	6.4k	20 repos	~1k	Automated safety check: Pass	MIT	today

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180k GitHub starsUsed in 51 repos~966 tokens
Testing & QAAuto-check passed
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Diagnosis loop for hard bugs and performance regressions. An agent skill from fossasia/eventyay-interpretation.
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A skill your agent uses when writing new features, fixing bugs, or refactoring code.
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Context Driven Development
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Questions about Add Tool

What does Add Tool do?

Guide for adding a new tool to OhMyCode. An agent skill from AlphaLab-USTC/OhMyCode. Add Tool is an agent skill from AlphaLab-USTC/OhMyCode. Guide for adding a new tool to OhMyCode.

When should I use Add Tool?

Add Tool fits situations like: user wants to create a custom tool.

How do I install Add Tool in Claude Code?

Run `npx skills add AlphaLab-USTC/OhMyCode --skill add-tool -a claude-code`. Or copy the skill folder (.agents/skills/add-tool in AlphaLab-USTC/OhMyCode) into .claude/skills/add-tool in your project. Claude Code loads it when a task matches its description.

How do I install Add Tool in Codex?

Run `npx skills add AlphaLab-USTC/OhMyCode --skill add-tool -a codex`. Or copy the skill folder (.agents/skills/add-tool in AlphaLab-USTC/OhMyCode) into .agents/skills/add-tool in your project. Codex loads it when a task matches its description.

Can I use Add Tool 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 AlphaLab-USTC/OhMyCode --skill add-tool -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/add-tool, .gemini/skills/add-tool, .github/skills/add-tool and .opencode/skills/add-tool in your project.

What does Add Tool need to run?

Going by SKILL.md and its folder, Add Tool needs Python for the scripts in its folder and the command-line tools its instructions call (python3 and git). Our summary lists: Python 3.

Does Add Tool access the network?

SKILL.md contains no URLs. Its commands use git, which can reach the network depending on how they are called. This is read from the text; nothing was executed.

Is Add Tool 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 Add Tool use?

Add Tool is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Add Tool use?

About 758 tokens (SKILL.md is roughly 3k 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 Add Tool?

Skills that share tags, products or a category with Add Tool: Web Application Testing (anthropics/skills, 180k stars), Diagnosing Bugs (fossasia/eventyay-interpretation, 1.6k stars), TDD (pietheinstrengholt/rssmonster, 564 stars) and TDD Workflow (hellangleZ/burn-in-cceverywhere-ralph, 112 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Add Tool?

AlphaLab-USTC (a GitHub user) maintains it in AlphaLab-USTC/OhMyCode, which has 131 GitHub stars. The repository holds 10 skills in this directory. The repository was last updated on April 2, 2026.

Source: AlphaLab-USTC/OhMyCode on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.

Install Add Tool

Facts

At a glance

What it does

When your agent uses it

Example prompts

Requirements

Workflow steps

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Add a New Tool to OhMyCode

When to Use

Prerequisites

Step-by-Step Guide

Step 1: Define the Tool

Step 2: Create the Tool File

Step 3: Write Tests (TDD)

Step 4: Verify

Step 5: Test End-to-End

Step 6: Commit

Key Requirements

Common Mistakes

Files

Compare with similar skills

Similar skills

More from AlphaLab-USTC/OhMyCode

Related

Questions about Add Tool