Agent skill · Trail of Bits

Modern Python Tooling skill for Claude Code, Codex and Cursor

Sets up Python projects with uv, ruff and ty, or migrates from pip, Poetry and mypy.

Officialname: modern-python★ 7.8k (repo)pushed 2026-10-24CC-BY-SA-4.0SKILL.md on GitHubchecked 2026-11-07

What it does, in the publisher's words

Configures Python projects with modern tooling (uv, ruff, ty). Use when creating projects, writing standalone scripts, or migrating from pip/Poetry/mypy/black.

The description field of the SKILL.md. The agent reads only this at startup and decides from it when to load the full skill.

Install Modern Python Tooling

The skills CLI copies the skill into the folder of each agent you pick (Claude Code, Codex, Cursor, Copilot, Gemini CLI, OpenCode, Windsurf...). Add -g for all projects. Needs Node.js 22.20+. docs

npx skills add trailofbits/skills --skill modern-python

This repo is a plugin marketplace. Inside Claude Code, add it and install the plugin that holds the skill (audit-context-building, building-secure-contracts, burpsuite-project-parser, chrome-mcp-troubleshooting...), or copy only this skill into ~/.claude/skills. docs

/plugin marketplace add trailofbits/skills
/plugin install <plugin>@trailofbits

# or only this skill:
npx skills add trailofbits/skills --skill modern-python -a claude-code

Download the skill folder, zip it, then Customize > Skills > + > Create skill > Upload a skill. Code execution must be on (Settings > Capabilities). docs

git clone --depth 1 https://github.com/trailofbits/skills.git /tmp/modern-python-src
cp -r /tmp/modern-python-src/plugins/modern-python/skills/modern-python ./modern-python
zip -r modern-python.zip modern-python

Codex reads skills from .agents/skills in the repo or ~/.agents/skills. Type $ in Codex to use one. docs

npx skills add trailofbits/skills --skill modern-python -a codex

gh skill (GitHub CLI 2.90+, preview) installs it for Copilot in VS Code, the CLI and the cloud agent. Copilot also reads .github/skills and ~/.copilot/skills. docs

gh skill install trailofbits/skills modern-python

Cursor reads .cursor/skills, .agents/skills and ~/.cursor/skills (and .claude/skills). It does not install loose skills from a GitHub URL, so copy it in. docs

npx skills add trailofbits/skills --skill modern-python -a cursor

Installs from the GitHub repo; --path picks this skill out of the repo. Default scope is user (all projects). docs

gemini skills install https://github.com/trailofbits/skills.git --path plugins/modern-python/skills/modern-python

OpenCode reads .opencode/skills, ~/.config/opencode/skills and the Claude and .agents folders. docs

npx skills add trailofbits/skills --skill modern-python -a opencode

Windsurf (now Devin Desktop) reads .devin/skills, .windsurf/skills and ~/.codeium/windsurf/skills. docs

npx skills add trailofbits/skills --skill modern-python -a windsurf

Works with

Claude Code, Claude.ai and Claude Desktop, Codex, GitHub Copilot, Cursor, Gemini CLI, OpenCode, Windsurf and other agents that read the open Agent Skills format.

What's in the SKILL.md

22 sections

When to Use This Skill
When NOT to Use This Skill
Anti-Patterns to Avoid
Decision Tree
Tool Overview
Security Tools
Quick Start: Minimal Project
Full Project Setup
1. Create Project Structure
2. Configure pyproject.toml
3. Install Dependencies
4. Add Makefile
Migration Guide
From requirements.txt + pip
From setup.py / setup.cfg
From flake8 + black + isort
From mypy / pyright
Quick Reference: uv Commands
Ad-hoc Dependencies with --with
Quick Reference: Dependency Groups
Best Practices Checklist
Read Next

Bundled files

agents/openai.yaml
assets/trail-of-bits-mark.svg
references/dependabot.md
references/migration-checklist.md
references/pep723-scripts.md
references/prek.md
references/pyproject.md
references/ruff-config.md
references/security-setup.md
references/testing.md
references/uv-commands.md
templates/dependabot.yml
templates/pre-commit-config.yaml

Loaded only when the instructions point to them.

Facts

Skill name: modern-python
Publisher: Trail of Bits (official)
Repo: trailofbits/skills
License: CC-BY-SA-4.0
SKILL.md size: 970 words, 329 lines
Bundled files: 13, 9 docs
Repo stars: 7.8k (as of 2026-10-24)
SKILL.md checked: 2026-11-07

More skills from trailofbits/skills

Agentic Actions Auditor: Audits GitHub Actions workflows that run AI agents for prompt-injection and privilege risks.
CodeQL Scan: Builds a CodeQL database and runs data-flow and taint analysis to find vulnerabilities.
Constant-Time Analysis: Finds timing side channels in cryptographic code, such as branches on secret values.
Differential Security Review: Security review of a diff that weighs blast radius, call sites and test coverage of changed code.
Property-Based Testing: Writes and debugs property-based tests with Hypothesis, fast-check, proptest and similar tools.
Semgrep Rule Creator: Writes custom Semgrep rules to catch specific bug or vulnerability patterns.
Sharp Edges: Flags error-prone APIs, risky defaults and footgun designs that invite security mistakes.

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Subagent-Driven Development · Jesse Vincent (obra)

FAQ

What does the modern-python skill do?+

Sets up Python projects with uv, ruff and ty, or migrates from pip, Poetry and mypy. In its own SKILL.md, Trail of Bits describes it as: "Configures Python projects with modern tooling (uv, ruff, ty). Use when creating projects, writing standalone scripts, or migrating from pip/Poetry/mypy/black."

How do I install the modern-python skill?+

Run npx skills add trailofbits/skills --skill modern-python and pick your agents, or use the tab for your agent above. In Claude Code the skill ends up in ~/.claude/skills/modern-python/SKILL.md; in Codex and Cursor in .agents/skills/modern-python/.

Does Modern Python Tooling work in Codex, Cursor and Copilot, or only Claude?+

It's a standard SKILL.md, so any agent that reads the Agent Skills format can use it: Claude Code, the Claude apps, Codex, GitHub Copilot, Cursor, Gemini CLI, OpenCode, Windsurf and more.

Who maintains Modern Python Tooling?+

Trail of Bits, the company or project behind it, in the trailofbits/skills repo on GitHub, last pushed 2026-10-24. License: CC-BY-SA-4.0.

Read a skill's SKILL.md and scripts before you install it: skills aren't verified by any agent vendor. Claude skills marketplace · How to install skills · MCP servers