How do I learn a new repo quickly?

Learning a new repository quickly means finding the handful of real, load-bearing paths through it instead of reading the file tree top to bottom. DiffGuardian speeds that with three features built for exactly this: asking plain-English questions about the whole repository, tracing a real feature across the files it touches, and mapping what a module actually depends on.

#A method for a new repo, without any tool

1. Find the entry points before anything else. The routes, the CLI commands, the main function, the job handlers — the places execution actually starts. Everything else exists to serve one of these.
2. Read the README and any architecture docs, then verify them against the code. Documentation drifts. Treat it as a hypothesis about how the system works, not a fact, until you have confirmed it against a real code path.
3. Pick one real, user-facing flow and follow it end to end. Choose something concrete — a sign-up, a checkout, a single API request — and trace it from entry point to where it stops, across every file it touches. One flow followed completely teaches you more than ten files read in isolation.
4. Identify the boundaries. What talks to the database, what calls an external service, and what is pure logic with no side effects. Boundaries are where most bugs and most risk concentrate.
5. Check what is actively changing. Recent commit history for the area you are studying tells you what is stable and what is still being figured out — treat the stable parts as more trustworthy to build on.
6. Read a handful of tests for the area you are learning. A test asserts the intended behavior directly, which is often faster to read than inferring intent from the implementation alone.
7. Ask targeted questions once you have done the above, not before. A specific question grounded in what you have already found gets a more useful answer than a general one.

#How DiffGuardian speeds this

• Steps 1, 2 and 4 — entry points, architecture and boundaries. Ask your codebase (Pro) indexes the whole repository into a local code knowledge graph and answers a plain-English question — how does authentication work across the app?, what does this service touch if I change it? — citing the real files the answer came from, and can draw a diagram of the architecture or the flow when that explains the answer better than prose.
• Step 3 — following a real flow end to end. Open a representative pull request for the area you are learning and use Trace It (Pro) to move across every file the feature it ships touches, in the order the code actually runs, with the diff shown at each step — a fast way to learn how a feature is actually wired, not just how you assume it is.
• Step 4 — what a module actually depends on. DiffGuardian's blast-radius view maps a changed file's dependencies from the diff alone — the changed files and the modules they import. With a local checkout, it also adds the upstream callers that flow into it, drawn solid, plus dashed API and channel edges. Open even a small pull request that touches the module you are learning and, with that checkout, the graph shows its real dependents — faster than grepping for imports by hand.

DiffGuardian is a desktop app for macOS, Windows and Linux, and works with pull requests on GitHub, GitLab and Bitbucket.

#Limits

• Ask your codebase and Trace It are Pro features; on Basic they stay visible and open an upgrade prompt.
• Ask your codebase needs the repository indexed first — an initial indexing pass that runs entirely on your machine; later sessions reuse the index.
• The blast-radius view is built from a pull request's diff; it is not a standalone explorer for a file you have not opened a change against.