Add git branch creation functionality

Author: mikegehard

src/git/src/mcp_server_git/server.py

@@ -39,6 +39,11 @@ class GitLog(BaseModel):
     repo_path: str
     max_count: int = 10
 
+class GitCreateBranch(BaseModel):
+    repo_path: str
+    branch_name: str
+    base_branch: str | None = None
+
 class GitTools(str, Enum):
     STATUS = "git_status"
     DIFF_UNSTAGED = "git_diff_unstaged"
@@ -47,6 +52,7 @@ class GitTools(str, Enum):
     ADD = "git_add"
     RESET = "git_reset"
     LOG = "git_log"
+    CREATE_BRANCH = "git_create_branch"
 
 def git_status(repo: git.Repo) -> str:
     return repo.git.status()
@@ -81,6 +87,15 @@ def git_log(repo: git.Repo, max_count: int = 10) -> list[str]:
         )
     return log
 
+def git_create_branch(repo: git.Repo, branch_name: str, base_branch: str | None = None) -> str:
+    if base_branch:
+        base = repo.refs[base_branch]
+    else:
+        base = repo.active_branch
+
+    repo.create_head(branch_name, base)
+    return f"Created branch '{branch_name}' from {base.name}"
+
 async def serve(repository: Path | None) -> None:
     logger = logging.getLogger(__name__)
 
@@ -132,6 +147,11 @@ async def list_tools() -> list[Tool]:
                 description="Shows the commit logs",
                 inputSchema=GitLog.schema(),
             ),
+            Tool(
+                name=GitTools.CREATE_BRANCH,
+                description="Creates a new branch from an optional base branch",
+                inputSchema=GitCreateBranch.schema(),
+            ),
         ]
 
     async def list_repos() -> Sequence[str]:
@@ -218,6 +238,17 @@ async def call_tool(name: str, arguments: dict) -> list[TextContent]:
                     text="Commit history:\n" + "\n".join(log)
                 )]
 
+            case GitTools.CREATE_BRANCH:
+                result = git_create_branch(
+                    repo,
+                    arguments["branch_name"],
+                    arguments.get("base_branch")
+                )
+                return [TextContent(
+                    type="text",
+                    text=result
+                )]
+
             case _:
                 raise ValueError(f"Unknown tool: {name}")