Map Codebase

SkillDocs & knowledge

Deep architecture report that fans out parallel inspections across different aspects of the codebase (structure, tech stack, APIs, patterns, data flow, dependencies, testing) and synthesizes findings into a comprehensive document at .turbo/codebase-map.md and .turbo/codebase-map.html. Use when the user asks to \"map the codebase\", \"map codebase\", \"architecture report\", \"codebase overview\", \"architecture overview\", \"what am I looking at\", or \"explain this codebase\".

Available today. Use it from your connected AI after setup.

Connect ahel once, and every AI you use reads what you have installed.

Then ask your AI: use the Map Codebase skill

What this skill tells your AI

The instructions your AI receives, as published by tobihagemann/turbo in codex/skills/map-codebase/SKILL.md and read by ahel’s review.

Deep architecture report. Fans out parallel inspections across different aspects of the codebase, synthesizes their findings, and writes .turbo/codebase-map.md and .turbo/codebase-map.html. Analysis-only.

Task Tracking

At the start, use update_plan to track each phase, restating any remaining steps of a parent workflow alongside them:

  1. Scope
  2. Launch inspection agents
  3. Synthesize and generate markdown report
  4. Generate HTML report

Step 1: Scope

If $ARGUMENTS specifies paths, use those directly (skip the question).

Otherwise, use request_user_input to confirm scope:

  • Entire codebase — inspect everything
  • Specific paths — user provides directories or file patterns

Once scope is determined, glob for source files in the selected scope. Exclude generated and vendored directories (node_modules/, dist/, build/, vendor/, __pycache__/, .build/, DerivedData/, target/, .tox/, and others appropriate to the project).

Build a file manifest grouped by top-level source directory. This manifest is shared with all agents as a starting point. Agents may explore beyond it based on what they discover.

Step 2: Launch Inspection Agents

Before dispatching, read the project's test configuration and CI workflow to identify any test tier that resets a shared external resource between tests, such as a database, a fixed port, or a cache. Such tiers have no cross-process interlock, so agents running them concurrently wipe each other's state and return failures that look like real defects. Name any such tier to every agent as off-limits.

Issue all 7 spawn_agent calls below in one batch, then collect their results with wait_agent. Do not issue one and await its result before issuing the rest. Each sub-agent inherits the parent model. Each agent receives the scoped file manifest and its exploration brief, and its prompt directs it to treat the shared working tree and its git index as read-only — any empirical check runs in an isolated git worktree created under $TMPDIR and discarded afterward. HEAD stays where it is: read other refs with git show <ref>:<path> rather than git checkout or git switch. Give that worktree its own dependency install rather than reaching the shared tree's install by any route: removing a worktree deletes through symlinks, and a redirected suite writes into the shared install. When its own install is not possible, the check is left unrun and reported as such. Afterward the agent verifies that git worktree list no longer shows the worktree, that git status --short is clean, that HEAD is still on the branch it started on, and that the shared tree's dependency directory still resolves (a destroyed install leaves git status clean, since it is gitignored). Damage the agent cannot repair is reported with the exact repair command in place of findings.

Dimensions

Launch one agent per dimension. Each agent's prompt provides the file manifest and the exploration brief below. Agents explore adaptively: go deeper where complexity warrants it, stay high-level where things are straightforward. Findings should be concrete (reference specific files and directories) rather than generic.

#DimensionExploration Brief
1Project StructureMap directory layout, module organization, naming conventions, and file roles. Identify the organizing principle (feature-based, layer-based, hybrid). Note generated or build output directories.
2Tech Stack and Build SystemIdentify languages, frameworks, package managers, build tools, and runtime requirements. Note version constraints and compatibility targets.
3Entry Points and Public APIFind how the system is invoked: CLI commands, HTTP endpoints, event handlers, exported modules, main functions. Map the public surface area.
4Core Abstractions and PatternsIdentify key types, classes, interfaces, and design patterns. Note architectural patterns (MVC, plugin system, pipeline, etc.) and how they shape the code.
5Data Flow and StateTrace how data enters, transforms, persists, and exits the system. Identify state management approaches, storage layers, and data boundaries.
6External Dependencies and IntegrationsMap third-party services, APIs, databases, and system boundaries. Note how external dependencies are abstracted or coupled.
7Testing and Quality InfrastructureDescribe the test strategy: frameworks, coverage approach, test organization, CI/CD pipeline. Note gaps or unusual patterns.

Each agent writes its findings as structured markdown with sections and subsections.

Step 3: Synthesize and Generate Markdown Report

After all agents complete:

  1. Read all agent reports.
  2. Identify cross-cutting themes, connections between dimensions, and architectural trade-offs.
  3. Write a brief executive summary (3-5 sentences) capturing the system's essential character.
  4. Resolve contradictions or overlaps between dimension reports.
  5. Write .turbo/codebase-map.md using the report template. Output the executive summary as text before writing the file.

Report Template

# Codebase Map

**Date:** <date>
**Scope:** <what was inspected>

## Executive Summary

<3-5 sentences: what the system is, how it's organized, what architectural choices define it>

## Project Structure

<from dimension 1>

## Tech Stack

<from dimension 2>

## Entry Points and API

<from dimension 3>

## Core Abstractions

<from dimension 4>

## Data Flow

<from dimension 5>

## External Dependencies

<from dimension 6>

## Testing and Quality

<from dimension 7>

## Cross-Cutting Observations

<themes, trade-offs, and connections identified during synthesis>

Step 4: Generate HTML Report

Convert the markdown report into a styled, interactive HTML page.

  1. Run the $frontend-design skill to load design principles.
  2. Read .turbo/codebase-map.md for the full report content.
  3. Write a self-contained .turbo/codebase-map.html (single file, no external dependencies beyond Google Fonts) that presents the architecture report with:
    • Executive summary card
    • Sticky navigation between sections
    • Collapsible dimension sections
    • [hidden] { display: none !important; } in the base styles, so a section whose own CSS sets a display value still hides
    • File and directory references as styled inline code
    • Entrance animations and hover states
    • Print-friendly styles via @media print
    • Responsive layout for mobile

Rules

  • If any agent fails, proceed with findings from the remaining agents and note the failure in the report.
  • Each dimension agent operates independently. Overlapping observations from different angles are expected. The synthesis step resolves overlaps.
  • Does not modify source code, stage files, or commit.

Signals

GitHub stars
402
Forks
30
Last commit
Sep 2026
Advanced
Catalog kind
skill
Gateway key
map-codebase-tobihagemann
Source
github.com/tobihagemann/turbo