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name: create-branch description: Create and checkout a new git branch with smart validation and GitHub issue integration model: sonnet allowed-tools: Bash(git status), Bash(git branch), Bash(git checkout), Bash(git push), Bash(git rev-parse), Bash(git ls-remote), Bash(gh issue develop), Bash(gh issue list), Bash(gh issue view)

Language Conventions

Infer language style from the project:

• Analyze existing branches, commit messages, and documentation to detect the project's language variant (US English, UK English, etc.)
• Match the spelling conventions found in the project (e.g., "synchronize" vs "synchronise", "center" vs "centre")
• Maintain consistency with the project's established language style throughout branch names and command outputs

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Create Branch Command

This command creates and checks out a new git branch with intelligent validation and GitHub issue integration.

Priority: GitHub Issue Integration

IMPORTANT: If the user provides an issue number (e.g., "#123", "123", or "issue 123"), ALWAYS prioritise using GitHub CLI's issue development workflow:

1. Check for GitHub CLI availability:

   Copygh --version
   

   If not available, inform the user and fall back to manual branch creation.

2. Verify the issue exists:

   Copygh issue view <issue-number>
   

   Display issue title and status to confirm.

3. Create branch linked to issue:

   Copygh issue develop <issue-number> -c
   

   • The -c flag automatically checks out the newly created branch
   • GitHub automatically generates an appropriate branch name from the issue title
   • The branch is linked to the issue for better project tracking

4. Skip to remote push step (step 8 below)

Manual Branch Creation Workflow

If no issue number is provided, follow this workflow:

1. Check Repository Status

Copygit status

Verify:

• Clean working directory or acceptable uncommitted changes
• Current branch information
• Whether we're in a git repository

2. Get Branch Name Input

Ask the user for the desired branch name. Accept input in any format - the command will handle formatting and validation.

3. Auto-Detect and Apply Prefix

Analyse the branch name input for keywords and automatically add appropriate prefixes:

• feature/ - Keywords: "add", "implement", "create", "new", "feature"
• bugfix/ - Keywords: "fix", "bug", "resolve", "patch", "repair"
• hotfix/ - Keywords: "hotfix", "urgent", "critical", "emergency"
• chore/ - Keywords: "chore", "refactor", "update", "upgrade", "maintain"
• docs/ - Keywords: "docs", "documentation", "readme", "guide"

If the user's input already starts with a recognised prefix (feature/, bugfix/, etc.), keep it as-is.

4. Validate Branch Name

Apply comprehensive validation:

Kebab-Case Enforcement

• Convert to lowercase
• Replace spaces and underscores with hyphens
• Ensure format is: prefix/kebab-case-name

Character Validation

Reject branch names containing:

• Spaces (convert to hyphens)
• Special characters: ~, ^, :, ?, *, [, ], \, @{, ..
• Control characters or non-ASCII (except hyphens and slashes)
• Leading or trailing slashes or hyphens

Length Validation

• Minimum: 3 characters (excluding prefix)
• Maximum: 100 characters (total)

5. Check for Duplicates

Check both local and remote branches:

Copy# Check local branches
git branch --list "<branch-name>"

# Check remote branches
git ls-remote --heads origin "<branch-name>"

If branch exists:

• Locally: Offer to checkout existing branch instead
• Remotely: Warn user and suggest alternative name
• Both: Inform user and ask if they want to checkout or choose different name

6. Determine Base Branch

Use smart defaulting:

1. Check if main exists:

   Copygit rev-parse --verify main
   

2. If not, check if master exists:

   Copygit rev-parse --verify master
   

3. If neither exists, use current HEAD

4. Allow user to specify different base branch if needed (ask before creating)

7. Create and Checkout Branch

Copygit checkout -b <validated-branch-name> <base-branch>

Confirm successful creation with a message showing:

• Branch name
• Base branch used
• Current status

8. Remote Push Recommendation

Ask the user: "Would you like to push this branch to remote and set up tracking?"

If yes:

Copygit push -u origin <branch-name>

This enables:

• Remote backup of the branch
• Collaboration with team members
• GitHub PR creation workflow
• Branch visibility in GitHub UI

Error Handling

Provide clear, actionable error messages:

• Not a git repository: "This directory is not a git repository. Initialise one with git init or navigate to a repository."
• GitHub CLI not available: "GitHub CLI (gh) is not installed. Install it from https://cli.github.com or use manual branch creation."
• Issue not found: "Issue #123 not found. Check the issue number or create a branch manually."
• Invalid branch name: "Branch name contains invalid characters. Suggested: feature/valid-branch-name"
• Branch exists: "Branch feature/existing already exists. Switch to it with git checkout feature/existing or choose a different name."
• Network issues: "Unable to check remote branches. Proceeding with local creation only."

Examples

Example 1: GitHub Issue Integration

CopyUser: "Create a branch for issue #456"
Command: gh issue view 456
Output: #456 - Add user authentication (open)
Command: gh issue develop 456 -c
Output: Created and checked out branch: feature/456-add-user-authentication

Example 2: Manual with Auto-Prefix

CopyUser: "Create branch: fix login bug"
Analysis: Contains "fix" → apply "bugfix/" prefix
Validated: "bugfix/login-bug"
Command: git checkout -b bugfix/login-bug main

Example 3: Custom Prefix

CopyUser: "Create branch: docs/update readme"
Analysis: Already has "docs/" prefix → keep as-is
Validated: "docs/update-readme"
Command: git checkout -b docs/update-readme main

Best Practises

1. Always prioritise GitHub issue workflow when issue numbers are mentioned
2. Validate thoroughly before creating branches to avoid git errors
3. Use descriptive names that clearly indicate the purpose
4. Follow team conventions - check existing branch names for patterns
5. Push to remote early for backup and collaboration
6. Link branches to issues whenever possible for better project tracking