"""
GitHub Tool: Create Branch for Jira Issue
Creates a new Git branch based on Jira issue key
"""
from __future__ import annotations
from typing import Any, Dict
from mcp.server.fastmcp import FastMCP
from src.providers.github.github_api import github_api_post, github_api_get
from src.config.github_config import get_github_config, extract_repo_info
def register(mcp: FastMCP) -> None:
"""
Register the create_branch_for_issue tool with the MCP server.
Enables the LLM to create feature branches for Jira issues with standard naming convention.
"""
@mcp.tool(name="create_branch_for_issue")
async def create_branch_for_issue(
issue_key: str,
branch_name: str | None = None,
) -> Dict[str, Any]:
"""
Create a new Git branch for a Jira issue.
Args:
issue_key: The Jira issue key (e.g., "KAN-1") - used in default branch naming
branch_name: Optional custom branch name. If not provided, defaults to "feature/{issue_key}"
Returns:
Dictionary with success flag, branch data (issue_key, branch_name, ref), and checkout instructions
Raises:
RuntimeError: If unable to fetch base branch SHA or create the branch
"""
cfg = get_github_config()
owner, repo = extract_repo_info(cfg.repo_url)
# Use custom branch name or default to feature/{issue_key}
if not branch_name:
branch_name = f"feature/{issue_key.lower()}"
# Get the default branch SHA as base point for new branch - WHY: GitHub creates branches
# by pointing a ref to a specific commit SHA, must fetch this first
try:
default_branch_data = await github_api_get(
f"/repos/{owner}/{repo}/git/refs/heads/{cfg.default_branch}"
)
base_sha = default_branch_data["object"]["sha"]
except Exception as e:
raise RuntimeError(f"Failed to get base branch SHA for {cfg.default_branch}: {str(e)}") from e
# Create new branch at the base SHA
try:
body = {
"ref": f"refs/heads/{branch_name}",
"sha": base_sha,
}
result = await github_api_post(
f"/repos/{owner}/{repo}/git/refs",
json_body=body,
)
return {
"success": True,
"data": {
"issue_key": issue_key,
"branch_name": branch_name,
"ref": result.get("ref"),
},
"message": f"Branch {branch_name} created successfully.",
"next_step": f"git checkout {branch_name}",
}
except Exception as e:
raise RuntimeError(f"Failed to create branch {branch_name}: {str(e)}") from e
