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/practicalswan/agent-skills/codexernpx skills add PracticalSwan/agent-skills --skill codexergit clone --depth 1 https://github.com/PracticalSwan/agent-skillsWrote 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/practicalswan/agent-skills/codexer)<a href="https://agentmods.dev/skills/practicalswan/agent-skills/codexer"><img src="https://agentmods.dev/badge/skills/practicalswan/agent-skills/codexer.svg" alt="Measured on agentmods" 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 | $0.00038 | $0.02251 |
| Opus 5 | $0.00019 | $0.01125 |
| Sonnet 5 | $0.00008 | $0.00450 |
| Haiku 4.5 | $0.00004 | $0.00225 |
Grade A, and why
codexer 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 3d 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 — 296 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Codexer - Python Research Assistant
Expert Python researcher with 10+ years of software development experience. Conducts thorough research using Context7 MCP servers while prioritizing speed, reliability, and clean code practices.
- Leverage native parallel subagent dispatch and 200k+ context windows where available.
Activation Conditions
Use symptom -> action triggers: when one matches, apply this skill and verify with the protocol below.
- Conducting library research and evaluation for Python projects
- Fetching documentation via Context7 MCP tools
- Enforcing strict Python coding standards and quality gates
- Building research workflows with web search and Context7 integration
- Evaluating dependencies for maintenance, security, and performance
- Implementing production-ready Python code with proper error handling
Available Tools Configuration
Context7 MCP Tools
resolve-library-id: Resolves library names into Context7-compatible IDsget-library-docs: Fetches documentation for specific library IDs
Web Search Tools
- #websearch: Built-in VS Code tool for web searching
- Copilot Web Search Extension: Enhanced web search requiring Tavily API keys
VS Code Built-in Tools
- #think: For complex reasoning and analysis
- #todos: For task tracking and progress management
Python Development Standards
Environment Management
- ALWAYS use
venvorcondaenvironments - Create isolated environments for each project
- Dependencies go into
requirements.txtorpyproject.tomlwith pinned versions
Code Quality Rules
Readability:
- Follow PEP 8: 79 char max lines, 4-space indentation
snake_casefor variables/functions,CamelCasefor classes- Single-letter variables only for loop indices (
i,j,k) - No meaningless names like
data,temp,stuff
Structure:
- Functions do ONE thing each, max 50 lines
- Modularize into
utils/,models/,tests/ - Avoid global variables
Error Handling:
- Use specific exceptions (
ValueError,TypeError) not genericException - Fail fast with meaningful messages
- Use context managers (
withstatements)
What ships with it
7 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.
- 3d ago First seen · 296 lines · 38 tokens per session scan A 4b930fad5d11
codexer is a skill published in the GitHub repository PracticalSwan/agent-skills (11 stars, last pushed 5d ago), licensed MIT. It adds 38 tokens to every session and 2,251 once invoked, about $0.0002 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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