GitLab MCP Server

Instructions

Implementation Reference

• src/gitlab_mcp/server.py:887-928 (handler)

  The tool handler that exposes `compare_branches` as an MCP tool and processes the response to format the user output.

  @mcp.tool()
  def compare_branches(project_id: int | str, from_ref: str, to_ref: str) -> str:
      """比較兩個分支或 commit 的差異
  
      Args:
          project_id: 專案 ID 或路徑
          from_ref: 起始分支/commit
          to_ref: 目標分支/commit
      """
      try:
          client = get_client()
          data = client.compare_branches(project_id, from_ref, to_ref)
  
          commits = data.get("commits", [])
          diffs = data.get("diffs", [])
  
          lines = [f"比較 {from_ref} → {to_ref}："]
          lines.append(f"Commits: {len(commits)} 個 | 檔案變更: {len(diffs)} 個\n")
  
          if commits:
              lines.append("--- Commits ---")
              for c in commits[:20]:  # 限制最多顯示 20 個 commits
                  lines.append(f"- {c.get('short_id', 'N/A')} {c.get('title', 'N/A')}")
              if len(commits) > 20:
                  lines.append(f"... 還有 {len(commits) - 20} 個 commits")
  
          if diffs:
              lines.append("\n--- 檔案變更 ---")
              for d in diffs:
                  new_path = d.get("new_path", "")
                  if d.get("new_file"):
                      lines.append(f"  [新增] {new_path}")
                  elif d.get("deleted_file"):
                      lines.append(f"  [刪除] {new_path}")
                  elif d.get("renamed_file"):
                      lines.append(f"  [重新命名] {d.get('old_path', '')} → {new_path}")
                  else:
                      lines.append(f"  [修改] {new_path}")
  
          return "\n".join(lines)
      except GitLabAPIError as e:
          return f"比較分支失敗: {str(e)}"

• src/gitlab_mcp/gitlab_client.py:416-422 (helper)

  The GitLab API client method that performs the network request to compare branches.

  def compare_branches(
      self, project_id: int | str, from_ref: str, to_ref: str
  ) -> dict:
      """GET /projects/:id/repository/compare"""
      pid = self._resolve_project_id(project_id)
      params = {"from": from_ref, "to": to_ref}
      return self._get_json(f"/projects/{pid}/repository/compare", params=params)