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/kiraneswaran/engineering-skills/python-developmentnpx skills add KiranEswaran/engineering-skills --skill python-developmentgit clone --depth 1 https://github.com/KiranEswaran/engineering-skillsWhat 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 | $0.00083 | $0.01187 |
| Opus 5 | $0.00042 | $0.00593 |
| Sonnet 5 | $0.00017 | $0.00237 |
| Haiku 4.5 | $0.00008 | $0.00119 |
Grade C, and why
python-development scanned grade C with 2 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 2d 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.
Downloads and executes remote codehighSupply chain
curl | sh runs whatever the server returns today, which is not necessarily what it returned when this was reviewed.
curl -LsSf https://astral.sh/uv/install.sh | sh Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
curl -LsSf https://astral.sh/uv/install.sh | sh How it starts
The opening of the file, as written. The whole thing — 187 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Python Development
Guiding Principle
Apply features only when they add clarity, correctness, performance, or security. Prefer simple, intentional solutions (DRY, KISS, YAGNI, Fail Fast).
AI Assistant Guidelines
- Avoid Over-Engineering: Don't recommend boto3 client caching, async/await, or concurrency patterns unless explicitly requested or bottlenecks are evident
- Keep It Simple: Prefer stdlib over complex architectures
- Respect Context: Don't transform a 20-line script into a 200-line framework
Standards Quick Reference
| Aspect | Standard |
|---|---|
| Python Version | ≥ 3.12 |
| Shebang | #!/usr/bin/env -S uv run |
| Formatting | 4-space indents, 120 char line length |
| Linting | black, ruff, pylint (≥9.0) |
| Type Hints | Strict typing required |
| Docstrings | Google-style |
| Package Manager | uv (preferred) |
Type Hints (Python 3.12+)
Use built-in types instead of typing module:
# Modern Python 3.12+
def process(items: list[str], config: dict[str, int] | None = None) -> tuple[str, int]:
...
# Avoid (old style)
from typing import List, Dict, Optional, Tuple
def process(items: List[str], config: Optional[Dict[str, int]] = None) -> Tuple[str, int]:
...
Code Structure
#!/usr/bin/env -S uv run
"""
Module purpose and overview.
Workflow:
1. Load configuration
2. Validate inputs
3. Process data
"""
# Standard library
import logging
# Third-party
import requests
# Local
from utils import helper
def helper_function() -> None:
"""Helper functions first."""
pass
def main() -> int:
"""Main function last."""
return 0
if __name__ == "__main__":
sys.exit(main())
Key Patterns
Defensive Programming
# Validate inputs early (fail-fast)
def process_user(user_id: str | None) -> User:
if user_id is None:
raise ValueError("user_id is required")
# Continue processing...
What ships with it
4 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.
- 2d ago First seen · 187 lines · 83 tokens per session scan C 08fb70d5cfc7
python-development is a skill published in the GitHub repository KiranEswaran/engineering-skills (10 stars, last pushed 8mo ago), licensed MIT. It adds 83 tokens to every session and 1,187 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it C with 2 findings (downloads and executes remote code, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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