Prepare Branch Context

Build a comprehensive understanding of the current branch so you can handle followup requests with full context.

Steps

1. Identify the current branch and base branch:

   git branch --show-current
   git merge-base HEAD main
   

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2. Gather the diff from main:

   git diff main...HEAD --stat
   git diff main...HEAD
   

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   Read through the full diff carefully. Understand what files were changed, added, or removed, and what the changes do.

3. Review the commit history on this branch:

   git log main..HEAD --oneline
   

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   Read commit messages to understand the progression of changes.

4. Check for a related PR:

   gh pr list --head "$(git branch --show-current)" --json number,title,body,url,state,comments --jq '.[0]'
   

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   If a PR exists, read its title, description, and comments for additional context (acceptance criteria, discussion, review feedback).

5. Summarize your understanding to the user:

   • What this branch does (high-level purpose)
   • Key files and areas of the codebase affected
   • Notable decisions or patterns visible in the changes
   • Any open review comments or discussion from the PR
   • Current state (clean, uncommitted changes, etc.)

6. Signal readiness: Tell the user you're ready for followup questions or tasks related to this branch.

Rules

• Do NOT make any changes to files. This skill is read-only.
• Read the actual diff content, not just the stat summary. You need to understand the code changes.
• If there's no PR, that's fine — just skip that step and note it.
• If the diff is very large, focus on understanding the overall structure first, then read key files in detail.
• Keep the summary concise but thorough enough that you could confidently make changes to this branch.
• If the branch is main or has no divergence from main, tell the user there's nothing to analyze.