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/booklib-ai/booklib/effective-pythonnpx skills add booklib-ai/booklib --skill effective-pythongit clone --depth 1 https://github.com/booklib-ai/booklibWhat 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 | $0.00051 | $0.04689 |
| Opus 5 | $0.00026 | $0.02344 |
| Sonnet 5 | $0.00010 | $0.00938 |
| Haiku 4.5 | $0.00005 | $0.00469 |
Grade A, and why
effective-python 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 — 442 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Effective Python Skill
Apply the 90 items from Brett Slatkin's "Effective Python" (2nd Edition) to review existing code and write new Python code. This skill operates in two modes: Review Mode (analyze code for violations) and Write Mode (produce idiomatic Python from scratch).
Reference Files
This skill includes categorized reference files with all 90 items:
ref-01-pythonic-thinking.md— Items 1-10: PEP 8, f-strings, bytes/str, walrus operator, unpacking, enumerate, zip, slicingref-02-lists-and-dicts.md— Items 11-18: Slicing, sorting, dict ordering, defaultdict, missingref-03-functions.md— Items 19-26: Exceptions vs None, closures, *args/**kwargs, keyword-only args, decoratorsref-04-comprehensions-generators.md— Items 27-36: Comprehensions, generators, yield from, itertoolsref-05-classes-interfaces.md— Items 37-43: Composition, @classmethod, super(), mix-ins, public attrsref-06-metaclasses-attributes.md— Items 44-51: @property, descriptors, getattr, init_subclass, class decoratorsref-07-concurrency.md— Items 52-64: subprocess, threads, Lock, Queue, coroutines, asyncioref-08-robustness-performance.md— Items 65-76: try/except, contextlib, datetime, decimal, profiling, data structuresref-09-testing-debugging.md— Items 77-85: TestCase, mocks, dependency injection, pdb, tracemallocref-10-collaboration.md— Items 86-90: Docstrings, packages, root exceptions, virtual environments
How to Use This Skill
Before responding, read the relevant reference files based on the code's topic. For a general review, read all files. For targeted work (e.g., writing async code), read the specific reference (e.g., ref-07-concurrency.md).
Mode 1: Code Review
When the user asks you to review existing Python code, follow this process:
Step 1: Read Relevant References
Determine which chapters apply to the code under review and read those reference files. If unsure, read all of them.
What ships with it
18 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.
- evals/evals.json 6.0 KB
- evals/results.json 248 B
- examples/after.md 2.3 KB
- examples/before.md 1.0 KB
- ref-01-pythonic-thinking.md 5.3 KB
- ref-02-lists-and-dicts.md 3.9 KB
- ref-03-functions.md 5.5 KB
- ref-04-comprehensions-generators.md 6.1 KB
- ref-05-classes-interfaces.md 5.5 KB
- ref-06-metaclasses-attributes.md 6.0 KB
- ref-07-concurrency.md 6.5 KB
- ref-08-robustness-performance.md 6.9 KB
- ref-09-testing-debugging.md 7.0 KB
- ref-10-collaboration.md 4.8 KB
- references/api_reference.md 19 KB
- references/practices-catalog.md 17 KB
- references/review-checklist.md 18 KB
- scripts/lint.py 6.3 KB runs code
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 · 442 lines · 51 tokens per session scan A ddba7cc876f6
effective-python is a skill published in the GitHub repository booklib-ai/booklib (38 stars, last pushed 4mo ago), licensed MIT. It adds 51 tokens to every session and 4,689 once invoked, about $0.0003 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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