band: Skill for Claude Code

Implementation Agent

Implements a GitHub issue in a Band worktree. Each run does one piece of work: reads progress from the GitHub issue comment, picks the next task, implements it, commits, pushes, and updates progress. Designed to be called repeatedly — each invocation gets fresh context and picks up where the last one left off.

Prerequisites

• Inside a Band worktree (git worktree managed by Band)
• gh CLI authenticated with GitHub
• band CLI available
• Branch name encodes the issue number: <issue-number>-<summary> (e.g., 99-task-loop-mode)

Steps

1. Detect Issue and Repo

BRANCH=$(git branch --show-current)
ISSUE_NUMBER=$(echo "$BRANCH" | grep -oE '^[0-9]+')
REPO=$(gh repo view --json nameWithOwner -q .nameWithOwner)

If no issue number is found in the branch name, check the task prompt for a #<number> reference. If still not found, skip issue tracking and just work from the prompt.

Fetch the issue:

gh issue view $ISSUE_NUMBER --repo $REPO

2. Read Progress State

Check for an existing progress comment on the issue:

gh api repos/$REPO/issues/$ISSUE_NUMBER/comments \
  --jq '.[] | select(.body | contains("## Implementation Progress")) | {id, body}'

Also check the worktree state:

git log --oneline main..HEAD       # What's been committed
git status --porcelain              # Any uncommitted work
gh pr list --head $BRANCH --repo $REPO --json number,state,reviewDecision  # Existing PR?

3. Route by Current State

Based on what you find, take the appropriate action:

State A — PR exists and is approved: Go to step 8 (Merge and Clean Up).

State B — PR exists with review feedback: Go to step 7 (Handle PR Feedback).

State C — PR exists, CI failing: Go to step 7 (Handle PR Feedback — fix CI).

State D — PR exists, waiting for review: Nothing to do. Print "PR #N is waiting for review" and exit.

State E — No PR, progress comment exists with unchecked items: Go to step 5 (Implement Next Task).