codebase-docs

A documentation tool for creating and maintaining Markdown files in a codebase's docs/ folder. It maps the project's structure and explains where important behavior and data flows are implemented.

In plain words
What is it for?
Use it to document project architecture, directory structure, authentication, data flow, key abstractions, and other codebase details.
Why use it?
It gives developers and coding agents a navigable overview without requiring them to read every source file. This makes onboarding, debugging, and future changes easier to plan.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/espennilsen/pi/codebase-docs
Any agent
npx skills add espennilsen/pi --skill codebase-docs
Clone the repo
git clone --depth 1 https://github.com/espennilsen/pi

Made for: Claude Code, Codex.

Per session 158 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,589 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00158 $0.01589
Opus 5 $0.00079 $0.00794
Sonnet 5 $0.00032 $0.00318
Haiku 4.5 $0.00016 $0.00159

Measured 2d ago against content hash 00e64dc42f3a, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

codebase-docs 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 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.

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-docs/SKILL.md · 126 lines

How it starts

The opening of the file, as written. The whole thing — 126 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Codebase Documentation Skill

Generate and maintain a structured set of markdown files in docs/ that give AI agents (and humans) a fast, accurate understanding of a codebase without needing to search through source files.

Philosophy

The docs you produce are a map, not the territory. They should let an AI agent answer questions like "where does authentication happen?", "how does data flow from API to database?", or "what are the key abstractions?" — without reading every file. Optimize for navigability and accuracy over exhaustiveness.

When to Use This Skill

  • User asks to document a codebase or project
  • User wants to update existing docs after making changes
  • User wants AI-friendly project documentation
  • User mentions docs/ directory maintenance
  • User wants architecture or structural documentation

Step 1: Assess the Codebase

Before writing anything, understand what you're documenting.

  1. Read the project root — check for existing README, package.json/Cargo.toml/pyproject.toml, config files, and any existing docs/ directory
  2. Map the directory structure — identify source directories, test directories, config, scripts, assets
  3. Identify the tech stack — languages, frameworks, key dependencies, build tools
  4. Find entry points — main files, route definitions, CLI entry points, exported modules
  5. Detect patterns — architecture style (MVC, microservices, monolith, plugin-based), state management, data layer

If a docs/ directory already exists, read it first. You'll be updating, not starting from scratch.

Step 2: Generate the Documentation Set

Create the docs/ directory with the files described below. Not every project needs every file — use judgment. A small CLI tool doesn't need DATA_MODEL.md, and a pure library doesn't need DEPLOYMENT.md.

Refer to references/doc-templates.md for the exact templates and structure for each file. Read that file before writing any documentation.

Required Files (always generate)

Read the full file on GitHub · 126 lines

Files

What ships with it

1 file 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. 2d ago First seen · 126 lines · 158 tokens per session scan A 00e64dc42f3a

Subscribe to this mod's changes

codebase-docs is a skill published in the GitHub repository espennilsen/pi (117 stars, last pushed 9d ago), licensed MIT. It adds 158 tokens to every session and 1,589 once invoked, about $0.0008 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.

Related

Other skills, from other repositories

systematic-debugging

Use when encountering any bug, test failure, or unexpected behavior, before proposing fixes.

obra/superpowers · 21 tokens

next-cache-components-adoption

Turn on Cache Components in a Next.js app and resolve the blocking routes it surfaces. Use when the user wants to enable, adopt, or migrate to Cache Components, flip the cacheComponents flag, work through a flood of blocking-prerender / instant validation errors, run the cache-components-instant-false codemod, or…

vercel/next.js · 95 tokens

babysit-pr

Babysit a GitHub pull request after creation by continuously polling review comments, CI checks/workflow runs, and mergeability state until the PR is merged/closed or user help is required. Diagnose failures, retry likely flaky failures up to 3 times, auto-fix/push branch-related issues when appropriate, and keep…

openai/codex · 114 tokens

imagegen

Generate or edit raster images when the task benefits from AI-created bitmap visuals such as photos, illustrations, textures, sprites, mockups, or transparent-background cutouts. Use when Codex should create a brand-new image, transform an existing image, or derive visual variants from references, and the output…

openai/codex · 113 tokens

cpu-profile-analysis

Analyze V8/Chrome CPU profiles (.cpuprofile) and DevTools trace files (Trace-.json). Use when: profiling performance, investigating slow functions, comparing code paths, finding bottlenecks, analyzing timeToRequest, understanding call trees from sampling profiler data, analyzing layout/paint/rendering, investigating…

microsoft/vscode · 71 tokens

next-cache-components-optimizer

Drive a Next.js route to instant navigation by setting up an agentic loop, under Cache Components / PPR, on initial load (hard navigation) and client-side navigation (soft navigation). Encode the goal as a failing @next/playwright instant() e2e and work it to green, one verified route at a time; the shipped test then…

vercel/next.js · 170 tokens