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 agentmods add skills/spillwavesolutions/agent-brain/mastering-python-skillnpx skills add SpillwaveSolutions/agent-brain --skill mastering-python-skillgit clone --depth 1 https://github.com/SpillwaveSolutions/agent-brainWhat 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 | $0.00127 | $0.01446 |
| Opus 5 | $0.00063 | $0.00723 |
| Sonnet 5 | $0.00025 | $0.00289 |
| Haiku 4.5 | $0.00013 | $0.00145 |
Grade A, and why
mastering-python-skill 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 yesterday.
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 — 142 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Mastering Python Skill
Production-ready Python patterns with runnable code examples.
Contents
Workflow
Phase 1: Setup
-
Verify Python version
python --version # Require 3.10+, prefer 3.12+ -
Create and activate virtual environment
python -m venv .venv && source .venv/bin/activate -
Install dependencies
poetry install # or: pip install -r requirements.txt
Phase 2: Develop
-
Reference appropriate patterns:
- Types → type-systems.md
- Async → async-programming.md
- APIs → fastapi-patterns.md
- DB → database-access.md
-
Follow project structure from project-structure.md
Phase 3: Validate
-
Run quality checks
ruff check . && ruff format --check . mypy src/ -
Run tests with coverage
pytest -v --cov=src --cov-report=term-missing
Phase 4: Deploy
-
Build and verify package
python -m build && twine check dist/* -
Deploy per docker-deployment.md or ci-cd-pipelines.md
Pre-Completion Checklist:
- [ ] All tests pass
- [ ] mypy reports no errors
- [ ] ruff check clean
- [ ] Coverage ≥80%
- [ ] No security warnings in dependencies
Reference Files
| Category | Files | Key Topics |
|---|---|---|
| Foundations | syntax-essentials, type-systems, project-structure, code-quality | Variables, type hints, generics, src layout, ruff, mypy |
| Patterns | async-programming, error-handling, decorators, context-managers, generators | async/await, exceptions, Result type, with statements, yield |
| Testing | pytest-essentials, mocking-strategies, property-testing | Fixtures, parametrize, unittest.mock, Hypothesis |
| Web APIs | fastapi-patterns, pydantic-validation, database-access | Dependencies, middleware, validators, SQLAlchemy async |
| Packaging | poetry-workflow, pyproject-config, docker-deployment | Lock files, PEP 621, multi-stage builds |
| Production | ci-cd-pipelines, monitoring, security | GitHub Actions, OpenTelemetry, OWASP, JWT |
What ships with it
28 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.
- .skilz-manifest.yaml 387 B
- references/foundations/code-quality.md 14 KB
- references/foundations/project-structure.md 15 KB
- references/foundations/syntax-essentials.md 19 KB
- references/foundations/type-systems.md 14 KB
- references/packaging/docker-deployment.md 17 KB
- references/packaging/poetry-workflow.md 14 KB
- references/packaging/pyproject-config.md 12 KB
- references/patterns/async-programming.md 15 KB
- references/patterns/context-managers.md 21 KB
- references/patterns/decorators.md 20 KB
- references/patterns/error-handling.md 20 KB
- references/patterns/generators.md 21 KB
- references/production/ci-cd-pipelines.md 16 KB
- references/production/monitoring.md 25 KB
- references/production/security.md 32 KB
- references/testing/mocking-strategies.md 32 KB
- references/testing/property-testing.md 30 KB
- references/testing/pytest-essentials.md 21 KB
- references/web-apis/database-access.md 27 KB
- references/web-apis/fastapi-patterns.md 19 KB
- references/web-apis/pydantic-validation.md 22 KB
- sample-cli/async_fetcher.py 7.7 KB runs code
- sample-cli/code_validator.py 8.3 KB runs code
- sample-cli/config_loader.py 9.7 KB runs code
- sample-cli/db_cli.py 13 KB runs code
- sample-cli/README.md 4.1 KB
- TOC.md 6.7 KB
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.
- yesterday First seen · 142 lines · 127 tokens per session scan A 18af56abd3d7
mastering-python-skill is a skill published in the GitHub repository SpillwaveSolutions/agent-brain (117 stars, last pushed 2d ago), licensed MIT. It adds 127 tokens to every session and 1,446 once invoked, about $0.0006 per session on Opus 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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