codebase-map

A short orientation map for an unfamiliar codebase or subsystem. It explains the project’s purpose, starting points, structure, important terms, risky areas, and ways to run and test it.

In plain words
What is it for?
Use it when joining a repository, exploring an unfamiliar subsystem, or reviewing a pull request that touches unknown code.
Why use it?
It reduces the time and risk involved in changing code you do not yet understand.

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/yuri-semenenko/ai-engineering-workspace/codebase-map
Any agent
npx skills add yuri-semenenko/ai-engineering-workspace --skill codebase-map
Clone the repo
git clone --depth 1 https://github.com/yuri-semenenko/ai-engineering-workspace

Made for: Claude Code, Codex.

Per session 189 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,033 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 $0.00189 $0.01033
Opus 5 $0.00095 $0.00517
Sonnet 5 $0.00038 $0.00207
Haiku 4.5 $0.00019 $0.00103

Measured yesterday against content hash 555e4ef2fe41, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

codebase-map 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 yesterday.

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.

claude-code/.claude/skills/codebase-map/SKILL.md · 45 lines

How it starts

The opening of the file, as written. The whole thing — 45 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Codebase Map

Build a fast, honest orientation to code you don't know yet, so you (or an agent you're about to point at it) can work in it safely. This is reconnaissance for comprehension: what the code is, where it starts, how it flows, and what not to touch. It is a map, not a tour — pointers over prose, evidence over guesses.

How to run (keep main context lean)

  1. Scope it. If a path argument was given, map that subtree; otherwise the whole repo. Read the obvious roots first: README, package.json (scripts + deps), the top-level layout, and any existing AGENTS.md / CLAUDE.md / architecture docs.
  2. Fan out, do not grep inline. Per the persona's session-hygiene rule, dispatch Explore subagents — one per subsystem or question (entry points, data flow, domain terms, tests/tooling) — each returning a compact findings list, not file dumps. This keeps large intermediate output out of the main conversation.
  3. Assemble the map from what came back. Merge, resolve contradictions rather than smoothing them over, and cite where each fact lives.

What the map captures

  • What it is. One paragraph: the purpose and the domain it serves. From the README and the shape of the code, not the marketing.
  • Entry points. Where execution actually starts — server/main, routes or pages, CLI commands, cron/queue workers, build entry. The "start here" files.
  • Architecture sketch. The handful of layers or modules that matter and how data flows between them. A few boxes and arrows in prose, not a file tree.
  • Domain glossary. The ubiquitous language: the 5-15 domain nouns and verbs that recur, one line each. The vocabulary you need to read the code and talk to the team.
  • Key seams. The stable interfaces and boundaries where behavior is substituted or extended (see /module-design for the vocabulary). Where you would attach a test or a new implementation.
  • Risky / don't-touch areas. Load-bearing, security-sensitive, or historically fragile code, and the invariants not to regress. Mark it; do not "fix" it (Chesterton's Fence).
  • How to run and test. Build/dev/test/single-test commands, local setup, required env vars — from repo evidence, not guesses. Say so when something is unknown.
  • Known tradeoffs. Existing TRADEOFF(...) annotations, TODOs of record, and documented debt (feeds /debt-ledger).

Read the full file on GitHub · 45 lines

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. yesterday First seen · 45 lines · 0 tokens per session scan A 555e4ef2fe41

Subscribe to this mod's changes

codebase-map is a skill published in the GitHub repository yuri-semenenko/ai-engineering-workspace (1 stars, last pushed 3d ago), licensed MIT. It adds 189 tokens to every session and 1,033 once invoked, about $0.0009 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.