fetch-diff

Fetch PR Diff

Fetches a pull request diff and adds line numbers for easier review-comment placement. Auto-generated files (lock files, protobuf-generated Java) are shown with masked diffs so review focuses on hand-written changes.

Usage

uv run "${CLAUDE_SKILL_DIR}/scripts/fetch_diff.py" <pr_url> [--files <pattern> ...]

The script is a self-contained PEP 723 script — uv run resolves its dependencies on demand; no install step is needed.

Examples

# Fetch the full diff
uv run "${CLAUDE_SKILL_DIR}/scripts/fetch_diff.py" https://github.com/owner/repo/pull/123

# Fetch only Python files
uv run "${CLAUDE_SKILL_DIR}/scripts/fetch_diff.py" https://github.com/owner/repo/pull/123 --files '*.py'

# Fetch only frontend files
uv run "${CLAUDE_SKILL_DIR}/scripts/fetch_diff.py" https://github.com/owner/repo/pull/123 --files 'src/server/js/*'

# Multiple patterns
uv run "${CLAUDE_SKILL_DIR}/scripts/fetch_diff.py" https://github.com/owner/repo/pull/123 --files '*.py' '*.ts'

The GitHub token is auto-detected from the GH_TOKEN environment variable or gh auth token.

Output Example

Regular file:

diff --git a/path/to/file.py b/path/to/file.py
index abc123..def456 100644
--- a/path/to/file.py
+++ b/path/to/file.py
@@ -10,7 +10,7 @@
10    10 |  import os
11    11 |  import sys
12    12 |  from typing import Optional
13       | -from old_module import OldClass
      14 | +from new_module import NewClass
14    15 |
15    16 |  def process_data(input_file: str) -> dict:

Auto-generated file (masked):

diff --git a/uv.lock b/uv.lock
index abc123..def456 100644
--- a/uv.lock
+++ b/uv.lock
[Auto-generated file - diff masked]

Deleted file (masked):

diff --git a/path/to/removed.py b/dev/null
index abc123..0000000 100644
--- a/path/to/removed.py
+++ /dev/null
[Deleted file - diff masked]

Line Annotation

Each line is annotated as old_line new_line | <marker> content:

• - marker (left number only) -> deleted line; comment with side=LEFT, line=old_line
• + marker (right number only) -> added line; comment with side=RIGHT, line=new_line
• No marker (both numbers) -> unchanged line; comment with side=RIGHT, line=new_line