Cartography 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/cartography.json
exists in the repo root.

If it exists: Skip to Step 3 (Detect Changes) - no need to re-initialize.

If it doesn't exist: Continue to Step 2 (Initialize).

Step 2: Initialize (Only if no state exists)

Analyze the repository structure - List files, understand directories
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
Run cartographer.py init:

bash

python3 ~/.config/opencode/skills/cartography/scripts/cartographer.py init \
  --root ./ \
  --include "src/**/*.ts" \
  --exclude "**/*.test.ts" --exclude "dist/**" --exclude "node_modules/**"

This creates:

```
.slim/cartography.json
```
- File and folder hashes for change detection
Empty
```
codemap.md
```
files in all relevant subdirectories

Delegate to Explorer agents - Spawn one explorer per folder to read code and fill in its specific
```
codemap.md
```
file.

Step 3: Detect Changes (If state already exists)

Run cartographer.py changes to see what changed:

bash

python3 ~/.config/opencode/skills/cartography/scripts/cartographer.py changes \
  --root ./

Review the output - It shows:
- Added files
- Removed files
- Modified files
- Affected folders
Only update affected codemaps - Spawn one explorer per affected folder to update its
```
codemap.md
```
.
Run update to save new state:

bash

python3 ~/.config/opencode/skills/cartography/scripts/cartographer.py update \
  --root ./

Step 4: Finalize Repository Atlas (Root Codemap)

Once all specific directories are mapped, the Orchestrator must create or update the root

codemap.md

. This file serves as the Master Entry Point for any agent or human entering the repository.

Map Root Assets: Document the root-level files (e.g.,
```
package.json
```
,
```
index.ts
```
,
```
plugin.json
```
) and the project's overall purpose.
Aggregate Sub-Maps: Create a "Repository Directory Map" section. For every folder that has a
```
codemap.md
```
, extract its Responsibility summary and include it in a table or list in the root map.
Cross-Reference: Ensure that the root map contains the absolute or relative paths to the sub-maps so agents can jump directly to the relevant details.

Codemap Content

Explorers are granted write permissions for

codemap.md

files during this workflow. Use precise technical terminology to document the implementation:

Responsibility - Define the specific role of this directory using standard software engineering terms (e.g., "Service Layer", "Data Access Object", "Middleware").
Design Patterns - Identify and name specific patterns used (e.g., "Observer", "Singleton", "Factory", "Strategy"). Detail the abstractions and interfaces.
Data & Control Flow - Explicitly trace how data enters and leaves the module. Mention specific function call sequences and state transitions.
Integration Points - List dependencies and consumer modules. Use technical names for hooks, events, or API endpoints.

Example codemap:

markdown

# src/agents/

## Responsibility
Defines agent personalities and manages their configuration lifecycle.

## Design
Each agent is a prompt + permission set. Config system uses:
- Default prompts (orchestrator.ts, explorer.ts, etc.)
- User overrides from ~/.config/opencode/oh-my-opencode-slim.json
- Permission wildcards for skill/MCP access control

## Flow
1. Plugin loads → calls getAgentConfigs()
2. Reads user config preset
3. Merges defaults with overrides
4. Applies permission rules (wildcard expansion)
5. Returns agent configs to OpenCode

## Integration
- Consumed by: Main plugin (src/index.ts)
- Depends on: Config loader, skills registry

Example Root Codemap (Atlas):

markdown

# Repository Atlas: oh-my-opencode-slim

## Project Responsibility
A high-performance, low-latency agent orchestration plugin for OpenCode, focusing on specialized sub-agent delegation and background task management.

## System Entry Points
- `src/index.ts`: Plugin initialization and OpenCode integration.
- `package.json`: Dependency manifest and build scripts.
- `oh-my-opencode-slim.json`: User configuration schema.

## Directory Map (Aggregated)
| Directory | Responsibility Summary | Detailed Map |
|-----------|------------------------|--------------|
| `src/agents/` | Defines agent personalities (Orchestrator, Explorer) and manages model routing. | [View Map](src/agents/codemap.md) |
| `src/features/` | Core logic for tmux integration, background task spawning, and session state. | [View Map](src/features/codemap.md) |
| `src/config/` | Implements the configuration loading pipeline and environment variable injection. | [View Map](src/config/codemap.md) |

cartography

NPX Install

SKILL.md Content

Cartography Skill

When to Use

Workflow

Step 1: Check for Existing State

Step 2: Initialize (Only if no state exists)

Step 3: Detect Changes (If state already exists)

Step 4: Finalize Repository Atlas (Root Codemap)

Codemap Content