# Fetch Diff

> Fetch PR diff with filtering and line numbers for code review. Use when this capability is needed.

- Skill: `tomevault-io/fetch-diff` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add tomevault-io/fetch-diff`
- Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/fetch-diff/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: tomevault-io (https://skillmd.com/u/tomevault-io)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/tomevault-io/fetch-diff

---


# Fetch PR Diff

Fetches a pull request diff and adds line numbers for easier review comment placement. Auto-generated files are shown with masked diffs.

## Usage

```bash
uv run skills fetch-diff <pr_url> [--files <pattern> ...]
```

Examples:

```bash
# Fetch the full diff
uv run skills fetch-diff https://github.com/mlflow/mlflow/pull/123

# Fetch only Python files
uv run skills fetch-diff https://github.com/mlflow/mlflow/pull/123 --files '*.py'

# Fetch only frontend files
uv run skills fetch-diff https://github.com/mlflow/mlflow/pull/123 --files 'mlflow/server/js/*'

# Multiple patterns
uv run skills fetch-diff https://github.com/mlflow/mlflow/pull/123 --files '*.py' '*.ts'
```

Token is auto-detected from `GH_TOKEN` env var 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]
```

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

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

---
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<!-- tomevault:4.0:skill_md:2026-04-11 -->