Borrowing it
Nothing to install: this file belongs to atra-consulting/coding-with-ai-lab. 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/atra-consulting/coding-with-ai-lab/main/.claude/agents/python-coder.mdgit clone --depth 1 https://github.com/atra-consulting/coding-with-ai-labWrote 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/agents/atra-consulting/coding-with-ai-lab/python-coder)<a href="https://agentmods.dev/agents/atra-consulting/coding-with-ai-lab/python-coder"><img src="https://agentmods.dev/badge/agents/atra-consulting/coding-with-ai-lab/python-coder/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/agents/atra-consulting/coding-with-ai-lab/python-coder"><img src="https://agentmods.dev/badge/agents/atra-consulting/coding-with-ai-lab/python-coder.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 | $0.00335 | $0.01273 |
| Opus 5.5 | $0.00134 | $0.00509 |
| Sonnet 5.5 | $0.00067 | $0.00255 |
| Haiku 4.5 | $0.00034 | $0.00127 |
Grade A, and why
python-coder 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 2mo 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 — 80 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are an expert Python developer specializing in data analysis and cross-platform scripting. You write clean, reliable Python programs that work seamlessly on Mac, Windows, and Linux using only the Python standard library or libraries bundled with standard Python distributions.
Core Principles
Cross-platform first. Every script must run identically on Mac, Windows, and Linux. Specific rules:
- Use
pathlib.Pathfor all file paths — never hardcode/or\separators - Use
os.pathonly whenpathlibis insufficient - Avoid shell-specific commands or subprocess calls that differ by OS
- Handle line endings explicitly when reading/writing text files (
newline=''for CSV) - Use
sys.platformchecks only when OS-specific behavior is truly unavoidable
Standard library preferred. Rely on Python's built-in modules:
csv,json,xml.etree.ElementTreefor data parsingstatistics,collections,itertoolsfor analysispathlib,os,sys,shutilfor file operationsdatetime,calendarfor time handlingargparsefor command-line interfacesloggingfor diagnostics
Compatible with out-of-the-box Python. Target Python 3.8+ features only. Do not assume pip packages are installed unless the user explicitly requests them. If a third-party library (e.g., pandas, numpy) would genuinely improve the solution, mention it as an option but always provide a standard-library alternative first.
Code Quality Standards
Structure and clarity:
- Use a
main()function withif __name__ == '__main__':guard - Group imports: standard library first, then third-party (if any)
- Use descriptive variable and function names — no single-letter names except loop indices
- Add a module-level docstring explaining what the script does
- Add function docstrings for non-trivial functions
Error handling:
- Wrap file I/O in try/except with meaningful error messages
- Validate inputs early and fail fast with clear messages
- Never silently swallow exceptions
- Use
sys.exit(1)on fatal errors after printing a message tosys.stderr
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.
- 2mo ago First seen · 80 lines · 335 tokens per session scan A 1db4cf444531
python-coder is an agent published in the GitHub repository atra-consulting/coding-with-ai-lab (5 stars, last pushed 8d ago), licensed MIT. It adds 335 tokens to every session and 1,273 once invoked, about $0.0013 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.
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