codebase-analysis

codebase-analysis is a skill for Codex from JakubMikolajek/codex-skills-collection. It costs 29 tokens per session (1,285 once invoked), scanned A, original, MIT.

A structured method for understanding an existing software repository, including its layout, dependencies, architecture, tests, infrastructure, and repeated code.

In plain words
What is it for?
It helps inspect whether a repository is a single project or a monorepo, identify frontend and backend parts, review scripts and dependencies, trace integrations, assess testing and security practices, and find dead or duplicated code.
Why use it?
It reduces the risk of making changes without understanding how the system is organized or where a change may have side effects.

Skill for Codex

Written for Codex: agents/openai.yaml present.

Good fit It helps inspect whether a repository is a single project or a…

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Install with agentmods
npx agentmods add skills/jakubmikolajek/codex-skills-collection/codebase-analysis
Install

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.

Any agent
npx skills add JakubMikolajek/codex-skills-collection --skill codebase-analysis
Clone the repo
git clone --depth 1 https://github.com/JakubMikolajek/codex-skills-collection

Made for: Codex.

Wrote 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.

agentmods badge for codebase-analysis

README.md
[![agentmods](https://agentmods.dev/badge/skills/jakubmikolajek/codex-skills-collection/codebase-analysis.svg)](https://agentmods.dev/skills/jakubmikolajek/codex-skills-collection/codebase-analysis)
Your own site
<a href="https://agentmods.dev/skills/jakubmikolajek/codex-skills-collection/codebase-analysis"><img src="https://agentmods.dev/badge/skills/jakubmikolajek/codex-skills-collection/codebase-analysis.svg" alt="Measured on agentmods" height="20"></a>
Per session 29 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,285 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00029 $0.01285
Opus 5 $0.00015 $0.00642
Sonnet 5 $0.00006 $0.00257
Haiku 4.5 $0.00003 $0.00128

Measured 6d ago against content hash 142ecb75cb06, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

codebase-analysis 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 6d 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.

skills/codebase-analysis/SKILL.md · 132 lines

How it starts

The opening of the file, as written. The whole thing — 132 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Codebase Analysis

This skill helps you analyse the codebase in a structured way, getting the most out of it. It focuses on architecture, patterns, code style, module separation, testing approach, dependencies and infrastructure.

Codebase Analysis Process

Use the checklist below and track your progress:

Analysis progress:
- [ ] Step 1: Check repository structure
- [ ] Step 2: Check dependencies
- [ ] Step 3: Check available scripts
- [ ] Step 4: Check high level architecture
- [ ] Step 5: Check backend code
- [ ] Step 6: Check frontend code
- [ ] Step 7: Check infrastructure code
- [ ] Step 8: Check third party integrations
- [ ] Step 9: Check testing approach
- [ ] Step 10: Check the security approach
- [ ] Step 11: Look for potential improvements
- [ ] Step 12: Check for deadcode and duplications

Step 1: Check repository structure

Go through the whole repository to identify and understand the structure of the repository. Find out what type of repository we work with. Is it monorepo or single system repository. Find out what type of the system in contains - frontend apps, backend apps, shared packages, infrastructure etc. Find out where dependencies and scripts files are stored. Find out where tests are stored (e2e, unit, integration). Find out where are the most crucial directories for each system.

Step 2: Check dependencies

Analyse all dependencies. Make sure to fully understand what frameworks, libraries, authentication systems etc. are used. Make sure to note which dependencies are out of date and could be an issue later on.

Step 3: Check available scripts

Check all available scripts. Find out what app running scripts we have. Find out what quality assurance scripts we have (tests, linting, formatting etc.) Understand the remaining scripts.

Step 4: Check high level architecture

Understand how the app architecture looks like based on the services, integrations and libraries. Create a diagram of the architecture you can figure out based on the code itself. Make sure to understand the internal and external communication patterns and practices used.

Read the full file on GitHub · 132 lines

Files

What ships with it

2 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.

Changes

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.

  1. 6d ago First seen · 132 lines · 29 tokens per session scan A 142ecb75cb06

Subscribe to this mod's changes

codebase-analysis is a skill published in the GitHub repository JakubMikolajek/codex-skills-collection (5 stars, last pushed yesterday), licensed MIT. It adds 29 tokens to every session and 1,285 once invoked, about $0.0001 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 2026-08-31.

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