# Pr Loc Breakdown
> PR Pure-Python LOC Breakdown
- Skill: `griddynamics/pr-loc-breakdown` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add griddynamics/pr-loc-breakdown`
- Raw SKILL.md: https://api.skillmd.com/api/skills/griddynamics/pr-loc-breakdown/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: griddynamics (https://skillmd.com/u/griddynamics)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/griddynamics/pr-loc-breakdown
---
# PR Pure-Python LOC Breakdown
Produce an accurate per-file breakdown of **pure Python code** added/removed in a
PR. "Pure" means **only executable Python**: it excludes markdown/docs/other
non-`.py` files, blank lines, whole-line comments, inline comments, and
docstrings (module / class / function string-literal statements).
## Why a script (not eyeballing the diff)
`git diff --stat` counts every changed line including blanks, comments, and
docstrings, so it overstates code churn. Counting by reading the diff by hand is
error-prone and not reproducible. This skill ships `count_py_loc.py`, which:
1. Resolves the base & head SHAs (via `gh` for a PR number, or `git merge-base`
for two refs — so churn that arrived from `main` moving forward is excluded).
2. Lists changed `.py` files with `git diff --name-only -- '*.py'`.
3. Reconstructs each file's **base** and **head** content (`git show [:`).
4. Strips comments + docstrings + blank lines from each version using Python's
`ast` (docstring line ranges) and `tokenize` (whole-line comments).
5. Diffs the two cleaned versions with `difflib.unified_diff(n=0)` and counts
`+`/`-` lines → real added/removed pure-code lines per file.
Because it diffs *cleaned* files, multi-line docstrings, reformatting, and
comment churn never inflate the numbers.
## Steps
1. Parse `$ARGUMENTS`:
- One integer (e.g. `277` or `#277`) → PR mode (resolves refs via `gh`).
- Two refs (e.g. `main feature-branch`) → ref mode.
- Empty → defaults to `merge-base(main, HEAD)..HEAD`.
2. Run the bundled script from the repo root:
```bash
python3 .claude/skills/pr-loc-breakdown/count_py_loc.py $ARGUMENTS
```
(use `python3`; `python` may not be on PATH)
Add `--json` for a machine-readable blob in addition to the table.
3. Present the table to the user. Lead with the total pure-Python added/removed,
then the per-file rows (already sorted by churn, largest first).
4. If the user asked only for additions (or only a subset), filter the reported
rows accordingly — do not re-count by hand.
## Notes
- Requires `gh` only in PR mode; ref mode and the default use `git` alone.
- The script self-heals on unparseable revisions: if a file version doesn't
parse (partial/invalid Python at that SHA), it falls back to a blank+comment
line filter and still strips full-line comments and blanks.
- Renames are counted as the diff between the old path's base content and the new
path's head content as Git reports them; pure-rename-only files show 0/0 and
are omitted.
- To reuse for non-PR comparisons (e.g. a tag range), pass two refs directly.
## Output Format
```
# Pure-Python LOC breakdown — PR #277
# base -> head
FILE +add -del net
------------------------------------ ------ ------ ------
backend/app/services/foo.py 120 14 +106
mcp_server/server.py 88 30 +58
...
------------------------------------ ------ ------ ------
TOTAL 512 110 +402
# N python file(s) with pure-code changes
```
]