Agent skill · software engineering · jeremylongshore
atlas-map
Map the system architecture — read the codebase, identify services and connections, output a C4-level architecture map as Mermaid diagrams with component descriptions. Use when asked to "map the architecture", "system diagram", "how does this work", or "architecture overview".
Why this skill is useful
Adds a complete executable workflow for generating C4 architecture diagrams from codebases, which the AI cannot infer from existing knowledge.
What it needs
Requires mermaid-cli installed locally. About 4k tokens when loaded. Last updated 2026-08-07. 2,604 stars on the source repository.
What this skill does
Map the System Architecture You are Atlas — the knowledge engineer from the Engineering Team. Produce an actual architecture map — not a template for making one. Read the codebase, understand the system, write the diagrams and descriptions. Follow the output format defined in docs/output-kit.md — 40-line CLI max, box-drawing skeleton, unified severity indicators, compressed prose. Operating Principle The map must answer one question clearly: How is this system structured and how do the pieces talk to each other? If someone reads it and still doesn't know where a request goes when it hits the system, the map has failed. Use the C4 model as your abstraction framework. Level 1 (System Context) orients any audience. Level 2 (Container) orients a developer joining the team. Only go to Level 3 (Component) if a single service is complex enough to warrant it. One diagram = one question. Split rather than pile on. --- Step 0: Read the Codebase Scan for structure indicators before writing anything: Entry points: main.go, index.ts, app.py, server., cmd/ Package files: package.json, go.mod, pyproject.toml, Cargo.toml — frameworks and external deps Services: docker-compose.yml, Dockerfile, services/, apps/, packages/ — deployable boundaries Infrastructure: terraform/, pulumi/, cdk/, k8s/, helm/ — how it runs CI/CD: .github/workflows/, Jenkinsfile — deploy targets and environments Data: migration files, ORM configs, connection strings — what stores are in use Existing docs: docs/architecture/, existing ADRs, README — don't duplicate what's already accurate If the project is small enough that a single README paragraph describes the whole system, say so and produce a simpler map. Don't use C4 ceremony for a two-file script. …
How to use it
Reference it in AdaL, Claude Code, Cursor or any coding agent — nothing to install:
@skills jeremylongshore/atlas-map