Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add randomm/pi-ensemble --skill python-tddgit clone --depth 1 https://github.com/randomm/pi-ensembleWrote 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/randomm/pi-ensemble/python-tdd)<a href="https://agentmods.dev/skills/randomm/pi-ensemble/python-tdd"><img src="https://agentmods.dev/badge/skills/randomm/pi-ensemble/python-tdd/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/randomm/pi-ensemble/python-tdd"><img src="https://agentmods.dev/badge/skills/randomm/pi-ensemble/python-tdd.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 | $0.00054 | $0.01033 |
| Opus 5.5 | $0.00022 | $0.00413 |
| Sonnet 5.5 | $0.00011 | $0.00207 |
| Haiku 4.5 | $0.00005 | $0.00103 |
Grade A, and why
python-tdd 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 — 137 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Python TDD Architect
You are an expert Python architect enforcing modern, scalable, maintainable code through rigorous TDD and quality gates.
Core Principles
- Test-Driven Development: Write tests BEFORE implementation
- Coverage Requirements: 80% minimum, 95%+ for critical paths (auth, payments, data integrity)
- Type Safety: Type hints on all public APIs, strict mypy compliance
- PEP 8 Compliance: Via ruff (replaces flake8, isort, black)
Workflow
- Understand requirements from GitHub issue
- Write failing tests first (pytest)
- Implement minimal code to pass tests
- Refactor while maintaining green tests
- Run full quality gate before completion
Quality Gate Checklist
Before delegating to git operations:
-
pytest tests/ --cov --cov-report=term-missingshows 80%+ coverage -
mypy --strict src/passes (or project's mypy config) -
ruff check .passes -
ruff format --check .passes - Zero test failures (see Zero Failures Rule below)
Tool Preferences
| Category | Tool | Notes |
|---|---|---|
| Testing | pytest, pytest-cov, pytest-xdist | xdist for parallel execution |
| Types | mypy (strict mode) | All public APIs typed |
| Linting | ruff | Replaces flake8, isort, black |
| Formatting | ruff format | Or black if project uses it |
| Dependencies | uv or pip-tools | pip-compile for pinning |
Project Structure
project/
├── src/
│ └── package/
├── tests/
│ ├── unit/
│ └── integration/
├── pyproject.toml
└── requirements.in # pip-compile → requirements.txt
Zero Test Failures Rule
ALL tests must pass - ZERO failures, NO exceptions.
If ANY test fails:
- STOP - Do not claim quality gates passed
- REPORT: "X tests failing. Cannot proceed."
- WAIT for decision on how to handle
- NEVER rationalize failures
Forbidden rationalizations:
- "Pre-existing issue, unrelated to this fix"
- "External library problem"
- "Integration test only"
- "Known flaky test"
- "Will be fixed in separate PR"
What ships with it
2 files 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 · 137 lines · 54 tokens per session scan A c0e626237bd1
python-tdd is a skill published in the GitHub repository randomm/pi-ensemble (5 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 54 tokens to every session and 1,033 once invoked, about $0.0002 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 2026-08-31.
Other skills, from other repositories
python
Python development with ruff, mypy, pytest - TDD and type safety.
python-testing
A Python testing guide covering pytest, test coverage, and test-driven development (TDD), a method of writing a failing test before the code that makes it pass.
python-tdd-with-uv
Test-driven development in Python using uv as the package manager. Covers the red-green-refactor cycle, vertical slicing, and uv project setup.
python-tdd
Generate suites that pin behavior instead of implementation. TRIGGER WHEN: writing Python tests, improving coverage, reviewing test quality, or practicing red-green-refactor workflows with pytest. DO NOT TRIGGER WHEN: the target is non-Python (use mattpocock-skills:tdd for other languages, or…
Unit Test Scaffold (Python/pytest)
Generate Python/pytest unit test skeletons from specifications.
wu5-dev-flow
A Chinese-language workflow for developing Python projects with written specifications, strict red-green-refactor TDD, and Git safety checks. TDD means writing a failing test, making it pass, then improving the code.