Onboard to an unfamiliar codebase by mapping its architecture, entry points, and data flow. Use when starting work in a new or unknown repository and you need a navigable mental model fast.
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Onboard to an unfamiliar codebase by mapping its architecture, entry points, and data flow. Use when starting work in a new or unknown repository and you need a navigable mental model fast.
argument-hint
(optional) a subsystem, feature, or question to focus on
Build a navigable map of this repository so the reader can find their way around and start contributing. Work from evidence in the repo, not assumptions about the stack.
Orient first
Identify the project type and stack from manifests and config (e.g. package.json, pyproject.toml, go.mod, Cargo.toml, pom.xml, Gemfile, Dockerfiles, CI config). Note the build, test, and run commands.
Read the README, docs, and any CONTRIBUTING or architecture notes before reading code, but verify their claims against the tree rather than trusting them blindly.
Get the shape of the tree: the top-level directories and what each is responsible for.
Map the architecture
Find the entry points: CLI mains, server bootstraps, route registrations, scheduled jobs, queue consumers, lambda/handler exports, UI roots. List them with file:line.
Identify the layers / modules and how they depend on each other (e.g. interface → service/domain → data access → external integrations). Note the boundaries that matter.
Pick one or two representative operations (or whatever the user asked to focus on) and follow them end to end: input → validation → core logic → persistence/external calls → response.
Show each path as a short sequence of file:line hops the reader can click through.
Call out where state lives (databases, caches, queues, external services) and how it's accessed.
Report
Produce, concisely:
Summary: one paragraph on what this project is and does.
Architecture map: the layers/modules and their responsibilities.
Entry points: where execution starts, with paths.
Key flows: the traced paths.
Conventions & gotchas: naming, patterns, where to add a new feature, anything surprising.
Where to look next: the 3 to 5 files most worth reading first.
Prefer precise file:line references over prose. Flag anything you were unsure about rather than guessing.