codemap

codemap is a skill for Claude Code, Codex from alvinunreal/oh-my-opencode-slim. It costs 34 tokens per session (1,611 once invoked), scanned A, original, MIT.

A repository-mapping tool that creates a hierarchical codemap of an unfamiliar codebase. A codemap is a structured overview of important source files and directories, showing how a repository is organized.

In plain words
What is it for?
Use it when documenting or initially understanding a repository, including checking existing codemap state and detecting changes before updating it.
Why use it?
Starting in an unfamiliar repository can make it hard to know where key code lives. The map narrows the overview to relevant implementation files and tracks later changes.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions subagents; mentions AGENTS.md; mentions OpenCode.

About the project

oh-my-opencode-slim is a plugin that coordinates multiple specialized AI agents inside OpenCode, assigning codebase exploration, documentation research, architecture review, design, and implementation to different agents. It is for developers who want agent teams to divide and reconcile software-development work while mixing models from different providers. The catalogue entries are the plugin’s bundled agents, skills, and instruction.

alvinunreal/oh-my-opencode-slim · 8,651 stars · on GitHub · ohmyopencodeslim.com

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/alvinunreal/oh-my-opencode-slim/codemap
Any agent
npx skills add alvinunreal/oh-my-opencode-slim --skill codemap
Clone the repo
git clone --depth 1 https://github.com/alvinunreal/oh-my-opencode-slim

Made for: Claude Code, 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 codemap

README.md
[![agentmods](https://agentmods.dev/badge/skills/alvinunreal/oh-my-opencode-slim/codemap.svg)](https://agentmods.dev/skills/alvinunreal/oh-my-opencode-slim/codemap)
Your own site
<a href="https://agentmods.dev/skills/alvinunreal/oh-my-opencode-slim/codemap"><img src="https://agentmods.dev/badge/skills/alvinunreal/oh-my-opencode-slim/codemap.svg" alt="Measured on agentmods" height="20"></a>
Per session 34 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,611 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 5.1 $0.00034 $0.01611
Opus 5 $0.00017 $0.00805
Sonnet 5 $0.00007 $0.00322
Haiku 4.5 $0.00003 $0.00161

Measured 6d ago against content hash 3befad8d7c35, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

codemap 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.

The scan reads SKILL.md. This mod also ships 2 executable files (scripts/codemap.mjs, scripts/codemap.test.ts), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

  • codemap — 100% identical, 0 lines differ
src/skills/codemap/SKILL.md · 164 lines

How it starts

The opening of the file, as written. The whole thing — 164 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Codemap Skill

You help users understand and map repositories by creating hierarchical codemaps.

When to Use

  • User asks to understand/map a repository
  • User wants codebase documentation
  • Starting work on an unfamiliar codebase

Workflow

Step 1: Check for Existing State

First, check if .slim/codemap.json exists in the repo root.

If it does not exist, check for legacy state at .slim/cartography.json.

If legacy state exists: move .slim/cartography.json to .slim/codemap.json, then continue with change detection.

If .slim/codemap.json exists: Skip to Step 3 (Detect Changes) - no need to re-initialize.

If neither file exists: Continue to Step 2 (Initialize).

Step 2: Initialize (Only if no state exists)

  1. Analyze the repository structure - List files, understand directories
  2. Infer patterns for core code/config files ONLY to include:
    • Include: src/**/*.ts, package.json, etc.
    • Exclude (MANDATORY): Do NOT include tests, documentation, or translations.
      • Tests: **/*.test.ts, **/*.spec.ts, tests/**, __tests__/**
      • Docs: docs/**, *.md (except root README.md if needed), LICENSE
      • Build/Deps: node_modules/**, dist/**, build/**, *.min.js
    • Respect .gitignore automatically
  3. Run codemap.mjs init:
node ~/.config/opencode/skills/codemap/scripts/codemap.mjs init \
  --root ./ \
  --include "src/**/*.ts" \
  --exclude "**/*.test.ts" --exclude "dist/**" --exclude "node_modules/**"

This creates:

  • .slim/codemap.json - File and folder hashes for change detection
  • Empty codemap.md files in all relevant subdirectories
  1. Delegate codemap writing to Fixer agents - Spawn one fixer per folder to read code and create or update its specific codemap.md file.

Step 3: Detect Changes (If state already exists)

  1. Run codemap.mjs changes to see what changed:
node ~/.config/opencode/skills/codemap/scripts/codemap.mjs changes \
  --root ./

Read the full file on GitHub · 164 lines

Files

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.

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 · 164 lines · 34 tokens per session scan A 3befad8d7c35

Subscribe to this mod's changes

codemap is a skill published in the GitHub repository alvinunreal/oh-my-opencode-slim (8,651 stars, last pushed yesterday), licensed MIT. It adds 34 tokens to every session and 1,611 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.