1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
|
# CLAUDE.md
## Project
Python project. Customize this section with your own description, layout,
and conventions.
**Typical layout:**
- `src/<package>/` or a top-level package directory — importable code
- `tests/` — pytest tests mirroring the package layout
- `pyproject.toml` — dependencies, tool config (ruff, pytest, coverage)
## Build & Test Commands
If the project has a Makefile, document targets here. Common pattern:
```bash
make test # run the pytest suite
make test FILE=tests/x.py # one file
make coverage # suite + coverage report
make lint # ruff across the tree
make typecheck # mypy (if the project adopts it)
make fmt # ruff format / black
```
Direct equivalents: `python3 -m pytest`, `pytest tests/test_x.py::test_name`,
`ruff check .`, `ruff format --diff .`, `mypy src/`.
## Language Rules
See rule files in `.claude/rules/`:
- `python-testing.md` — pytest conventions and fixture discipline
- `verification.md` — verify-before-claim-done discipline
## Git Workflow
Commit conventions: see `.claude/rules/commits.md` (author identity,
no AI attribution, message format).
Pre-commit hook in `githooks/` scans for secrets, syntax-checks staged Python,
and runs `ruff` when it's installed. Activate on a fresh clone with
`git config core.hooksPath githooks`.
## Problem-Solving Approach
Investigate before fixing. When diagnosing a bug:
1. Read the relevant module and trace what actually happens
2. Identify the root cause, not a surface symptom
3. Write a failing test that captures the correct behavior
4. Fix, then re-run tests
## Testing Discipline
TDD is the default: write a failing test before any implementation. If you can't
write the test, you don't yet understand the change. Details in
`.claude/rules/python-testing.md`.
## Editing Discipline
A PostToolUse hook syntax-checks every Python file after Edit/Write/MultiEdit
and blocks on a parse error, then runs `ruff` when it's installed. The hook
covers `.py`, `.pyi`, and extensionless files with a python shebang.
Type checking is not enforced by the hook — it needs the whole package and its
dependencies resolved, which is a build-scale operation rather than a
per-keystroke one. Run it via `make typecheck`.
Formatting is likewise not enforced: a project picks its own line length and
quote style, so blocking on an unconfigured default would impose a contested
choice. Adopt one per project in `pyproject.toml`.
## What Not to Do
- Don't add features beyond what was asked
- Don't refactor surrounding code when fixing a bug
- Don't use a bare `except:` or swallow an exception without handling it
- Don't use a mutable default argument (`def f(xs=[])`)
- Don't add comments to code you didn't change
- Don't commit `.env` files, credentials, or API keys — the pre-commit hook
catches common patterns but isn't a substitute for care
|
