PR Reference Generation Skill

Overview

Queries git for commit metadata and diff output, then produces a structured XML document. Both bash and PowerShell implementations are provided.

Use cases:

• PR description generation from commit history
• Code review preparation with structured diff context
• Work item discovery by analyzing branch changes
• Security analysis of modified files

After successful generation, include a file link to the absolute path of the XML output in the response.

Prerequisites

The repository must have at least one commit diverging from the base branch.

Platform	Runtime
macOS / Linux	Bash (pre-installed)
Windows	PowerShell 7+ (pwsh)
Cross-platform	PowerShell 7+ (pwsh)

Quick Start

Run the following command to generate a PR reference with default settings (compares against origin/main):

scripts/generate.sh
scripts/generate.sh --base-branch auto --merge-base --exclude-ext yml,json

scripts/generate.ps1
scripts/generate.ps1 -BaseBranch auto -MergeBase -ExcludeExt yml,json

Output saves to .copilot-tracking/pr/pr-reference.xml by default.

Parameters Reference

Parameter	Flag (bash)	Flag (PowerShell)	Default	Description
Base branch	--base-branch	-BaseBranch	origin/main (bash) / main (PowerShell)	Target branch for comparison. Use auto to detect remote default.
Merge base	--merge-base	-MergeBase	false	Use git merge-base for three-way comparison
Exclude markdown	--no-md-diff	-ExcludeMarkdownDiff	false	Exclude markdown files (*.md) from the diff
Exclude extensions	--exclude-ext	-ExcludeExt	(none)	Comma-separated extensions to exclude (e.g., yml,yaml,json,png)
Exclude paths	--exclude-path	-ExcludePath	(none)	Comma-separated path prefixes to exclude (for example, documentation and GitHub configuration directories)
Output path	--output	-OutputPath	.copilot-tracking/pr/pr-reference.xml	Custom output file path

Both defaults resolve to the same remote comparison. The PowerShell script automatically resolves origin/<branch> when a bare branch name is provided.

Additional Scripts Reference

After generating the PR reference, use these utility scripts to query the XML.

List Changed Files

Run the list script to extract file paths from the diff:

scripts/list-changed-files.sh                              # all changed files
scripts/list-changed-files.sh --type added                  # filter by single type
scripts/list-changed-files.sh --type added,modified,renamed  # filter by multiple types
scripts/list-changed-files.sh --exclude-type deleted         # exclude specific types
scripts/list-changed-files.sh --format markdown              # output as markdown table

scripts/list-changed-files.ps1                             # all changed files
scripts/list-changed-files.ps1 -Type Added                  # filter by single type
scripts/list-changed-files.ps1 -Type Added,Modified,Renamed # filter by multiple types
scripts/list-changed-files.ps1 -ExcludeType Deleted          # exclude specific types
scripts/list-changed-files.ps1 -Format Json                  # output as JSON

Parameter	Flag (bash)	Flag (PowerShell)	Default	Description
Input path	--input, -i	-InputPath	(auto)	Path to pr-reference.xml
Type filter	--type, -t	-Type	all	Change types to include (comma-separated: added, modified, etc.)
Exclude type	--exclude-type	-ExcludeType	(none)	Change types to exclude. Mutually exclusive with --type (non-all)
Format	--format, -f	-Format	plain	Output format: plain, json, or markdown

Read Diff Content

Run the read script to inspect diff content with chunking for large diffs:

scripts/read-diff.sh --info             # chunk info (count, line ranges)
scripts/read-diff.sh --chunk 1          # read a specific chunk
scripts/read-diff.sh --file src/main.ts  # extract diff for one file
scripts/read-diff.sh --summary          # file stats summary

scripts/read-diff.ps1 -Info              # chunk info
scripts/read-diff.ps1 -Chunk 1           # read a specific chunk
scripts/read-diff.ps1 -File "src/main.ts" # extract diff for one file

Output Format

The generated XML wraps commit metadata and unified diff output in a <commit_history> root element. See the reference guide for the complete XML schema, element reference, output path variations, and workflow integration patterns.

Troubleshooting

Symptom	Cause	Resolution
"No commits found" or empty XML	No diverging commits from base branch	Verify the branch has commits ahead of the base with git log base..HEAD
"Branch not found" error	Base branch ref missing locally	Run git fetch origin to update remote tracking refs
"git: command not found"	git is not on PATH	Install git or verify PATH includes the git binary directory