Orient in a codebase

Most bad changes start with a wrong assumption about the repository. A few minutes here prevents guessed commands, duplicated helpers and confusion over failures that already existed.

When to use

• First task in a repository, or in an area you have not read.
• You do not know how tests run, or which branch is current.

Skip this if you already did it for this area in the current session.

Steps

1. Check where you are. Run these and read the output:

   git status --short --branch
   git fetch origin
   git log --oneline -5

   If the branch is behind the default branch, note it. A search on a stale branch can miss code that exists.

2. Read the project's instructions. Look for AGENTS.md, CLAUDE.md, GEMINI.md, CONTRIBUTING.md and README.md. They override your habits.

3. Identify the stack from its manifest files.

   File	Stack	Look for commands in
   package.json	JavaScript or TypeScript	scripts
   pyproject.toml, requirements.txt	Python	[tool.*], tox.ini, Makefile
   go.mod	Go	Makefile, go test ./...
   Cargo.toml	Rust	cargo test
   pom.xml, build.gradle	Java or Kotlin	mvn test, ./gradlew test
   *.csproj, *.sln	.NET	dotnet test
   Gemfile	Ruby	Rakefile, bin/rspec
   composer.json	PHP	scripts

4. Find the commands CI runs. Read .github/workflows/, .gitlab-ci.yml or the equivalent. CI is the real definition of passing, and docs are often out of date. Note the commands for tests, lint, type checks and build.
5. Record a baseline. Run the tests for the area you will change, before you change anything. Write down what fails now. Without this, you cannot tell whether you caused a failure.
6. Find the code path. Search for a word from the task, such as a route, an error message or a UI label. Follow it from the entry point to storage. Read callers as well as the function itself.
7. Find the nearest example. Open the closest similar feature and its test. Copy their naming, structure, helpers and error handling.

Stop and ask when

• The task description does not match what the code does.
• The baseline is broken in a way that blocks your work.
• You cannot find how to run the tests after checking the manifest and CI.

Common mistakes

Report

Branch: <name>, <ahead/behind default branch>
Stack: <languages and frameworks>
Commands: test `<cmd>`, lint `<cmd>`, types `<cmd>`, build `<cmd>`
Baseline: <what passes, what already fails>
Code path: <entry point> -> <main files>
Pattern to follow: <nearest similar file>