oh-my-opencode-slim/docs/cartography.md

Cartography Skill

Cartography is a custom skill bundled with this repo.

It helps agents quickly build a high-quality mental model of an unfamiliar codebase by generating a structured codemap and tracking changes over time.

What it does

Cartography is designed for repository understanding and hierarchical codemap generation:

1. Selects relevant code/config files using LLM judgment
2. Creates .slim/cartography.json for change tracking
3. Generates codemap.md templates (per folder) for explorers to fill in

How to use

Cartography is installed automatically by the oh-my-opencode-slim installer when custom skills are enabled.

Run it (manual / local)

From a repo root (or with an explicit --root):

# Initialize mapping
python3 cartographer.py init --root /repo --include "src/**/*.ts" --exclude "node_modules/**"

# Check what changed
python3 cartographer.py changes --root /repo

# Update hashes
python3 cartographer.py update --root /repo

Outputs

.slim/cartography.json

A change-tracking file with hashes for files/folders.

codemap.md (per folder)

Empty templates created in each folder so an Explorer-style agent can fill in:

• Responsibility
• Design patterns
• Data/control flow
• Integration points

Screenshot

The existing screenshot lives in img/cartography.png.

Related

• src/skills/cartography/README.md and src/skills/cartography/SKILL.md contain the skill’s internal docs.
• codemap.md at the repo root is an example output/starting point.