Borrowing it
Nothing to install: this file belongs to AlphaLab-USTC/OhMyCode. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/AlphaLab-USTC/OhMyCode/main/.agents/skills/add-tool/SKILL.mdgit clone --depth 1 https://github.com/AlphaLab-USTC/OhMyCodeWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/alphalab-ustc/ohmycode/add-tool)<a href="https://agentmods.dev/skills/alphalab-ustc/ohmycode/add-tool"><img src="https://agentmods.dev/badge/skills/alphalab-ustc/ohmycode/add-tool/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/alphalab-ustc/ohmycode/add-tool"><img src="https://agentmods.dev/badge/skills/alphalab-ustc/ohmycode/add-tool.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00024 | $0.00788 |
| Opus 5.5 | $0.00010 | $0.00315 |
| Sonnet 5.5 | $0.00005 | $0.00158 |
| Haiku 4.5 | $0.00002 | $0.00079 |
Grade A, and why
add-tool scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 96 lines — stays where its author put it; the contents beside it link to each section on GitHub.
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.mdfor project conventions - Read
ohmycode/tools/base.pyto understandTool,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_safeclass attributesexecute()method with the actual logic
Step 3: Write Tests (TDD)
Create tests/tools/test_<tool_name>.py:
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
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
ohmycode -p "Use the <tool_name> tool to ..." --mode auto
Step 6: Commit
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 1mo ago First seen · 96 lines · 24 tokens per session scan A e7313d6cdcb8
add-tool is a skill published in the GitHub repository AlphaLab-USTC/OhMyCode (132 stars, last pushed 6mo ago), licensed MIT. It adds 24 tokens to every session and 788 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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