feat(git): add signed commit tool with GPG support

src/git/README.md

@@ -43,20 +43,29 @@ Please note that mcp-server-git is currently in early development. The functiona
      - `message` (string): Commit message
    - Returns: Confirmation with new commit hash
 
-6. `git_add`
+6. `git_commit_signed`
+    - Records changes to the repository and signs the commit with GPG
+    - Inputs:
+      - `repo_path` (string): Path to Git repository
+      - `message` (string): Commit message
+      - `key_id` (string, optional): GPG key ID to use for signing. If omitted, the default signing key configured in Git will be used.
+    - Behavior: Uses the Git CLI `-S`/`--gpg-sign` flag to create a GPG-signed commit. This passes through to the system's `git` and `gpg` configuration, so GPG must be available and configured on the host.
+    - Returns: Confirmation with new commit hash. If signing fails (for example, no GPG key is configured), the underlying Git command will raise an error.
+
+7. `git_add`
    - Adds file contents to the staging area
    - Inputs:
      - `repo_path` (string): Path to Git repository
      - `files` (string[]): Array of file paths to stage
    - Returns: Confirmation of staged files
 
-7. `git_reset`
+8. `git_reset`
    - Unstages all staged changes
    - Input:
      - `repo_path` (string): Path to Git repository
    - Returns: Confirmation of reset operation
 
-8. `git_log`
+9. `git_log`
    - Shows the commit logs with optional date filtering
    - Inputs:
      - `repo_path` (string): Path to Git repository
@@ -65,34 +74,36 @@ Please note that mcp-server-git is currently in early development. The functiona
      - `end_timestamp` (string, optional): End timestamp for filtering commits. Accepts ISO 8601 format (e.g., '2024-01-15T14:30:25'), relative dates (e.g., '2 weeks ago', 'yesterday'), or absolute dates (e.g., '2024-01-15', 'Jan 15 2024')
    - Returns: Array of commit entries with hash, author, date, and message
 
-9. `git_create_branch`
+10. `git_create_branch`
    - Creates a new branch
    - Inputs:
      - `repo_path` (string): Path to Git repository
      - `branch_name` (string): Name of the new branch
      - `base_branch` (string, optional): Base branch to create from (defaults to current branch)
    - Returns: Confirmation of branch creation
-10. `git_checkout`
+
+11. `git_checkout`
    - Switches branches
    - Inputs:
      - `repo_path` (string): Path to Git repository
      - `branch_name` (string): Name of branch to checkout
    - Returns: Confirmation of branch switch
-11. `git_show`
+
+12. `git_show`
    - Shows the contents of a commit
    - Inputs:
      - `repo_path` (string): Path to Git repository
      - `revision` (string): The revision (commit hash, branch name, tag) to show
    - Returns: Contents of the specified commit
 
-12. `git_branch`
-   - List Git branches
-   - Inputs:
-     - `repo_path` (string): Path to the Git repository.
-     - `branch_type` (string): Whether to list local branches ('local'), remote branches ('remote') or all branches('all').
-     - `contains` (string, optional): The commit sha that branch should contain. Do not pass anything to this param if no commit sha is specified
-     - `not_contains` (string, optional): The commit sha that branch should NOT contain. Do not pass anything to this param if no commit sha is specified
-   - Returns: List of branches
+13. `git_branch`
+    - List Git branches
+    - Inputs:
+      - `repo_path` (string): Path to the Git repository.
+      - `branch_type` (string): Whether to list local branches ('local'), remote branches ('remote') or all branches('all').
+      - `contains` (string, optional): The commit sha that branch should contain. Do not pass anything to this param if no commit sha is specified
+      - `not_contains` (string, optional): The commit sha that branch should NOT contain. Do not pass anything to this param if no commit sha is specified
+    - Returns: List of branches
 
 ## Installation
 

src/git/src/mcp_server_git/server.py

@@ -38,6 +38,14 @@ class GitCommit(BaseModel):
     repo_path: str
     message: str
 
+class GitCommitSigned(BaseModel):
+    repo_path: str
+    message: str
+    key_id: Optional[str] = Field(
+        None,
+        description="Optional GPG key ID to use for signing. If not provided, uses the default configured GPG key."
+    )
+
 class GitAdd(BaseModel):
     repo_path: str
     files: list[str]
@@ -97,6 +105,7 @@ class GitTools(str, Enum):
     DIFF_STAGED = "git_diff_staged"
     DIFF = "git_diff"
     COMMIT = "git_commit"
+    COMMIT_SIGNED = "git_commit_signed"
     ADD = "git_add"
     RESET = "git_reset"
     LOG = "git_log"
@@ -122,6 +131,16 @@ def git_commit(repo: git.Repo, message: str) -> str:
     commit = repo.index.commit(message)
     return f"Changes committed successfully with hash {commit.hexsha}"
 
+def git_commit_signed(repo: git.Repo, message: str, key_id: str | None = None) -> str:
+    # Use the git command directly for signing support
+    if key_id:
+        repo.git.commit("-S" + key_id, "-m", message)
+    else:
+        repo.git.commit("-S", "-m", message)
+    # Get the commit hash of HEAD
+    commit_hash = repo.head.commit.hexsha
+    return f"Changes committed and signed successfully with hash {commit_hash}"
+
 def git_add(repo: git.Repo, files: list[str]) -> str:
     if files == ["."]:
         repo.git.add(".")
@@ -142,9 +161,9 @@ def git_log(repo: git.Repo, max_count: int = 10, start_timestamp: Optional[str]
         if end_timestamp:
             args.extend(['--until', end_timestamp])
         args.extend(['--format=%H%n%an%n%ad%n%s%n'])
-        
+
         log_output = repo.git.log(*args).split('\n')
-        
+
         log = []
         # Process commits in groups of 4 (hash, author, date, message)
         for i in range(0, len(log_output), 4):
@@ -272,6 +291,11 @@ async def list_tools() -> list[Tool]:
                 description="Records changes to the repository",
                 inputSchema=GitCommit.model_json_schema(),
             ),
+            Tool(
+                name=GitTools.COMMIT_SIGNED,
+                description="Records changes to the repository with GPG signature",
+                inputSchema=GitCommitSigned.model_json_schema(),
+            ),
             Tool(
                 name=GitTools.ADD,
                 description="Adds file contents to the staging area",
@@ -343,7 +367,7 @@ def by_commandline() -> Sequence[str]:
     @server.call_tool()
     async def call_tool(name: str, arguments: dict) -> list[TextContent]:
         repo_path = Path(arguments["repo_path"])
-        
+
         # For all commands, we need an existing repo
         repo = git.Repo(repo_path)
 
@@ -383,6 +407,17 @@ async def call_tool(name: str, arguments: dict) -> list[TextContent]:
                     text=result
                 )]
 
+            case GitTools.COMMIT_SIGNED:
+                result = git_commit_signed(
+                    repo,
+                    arguments["message"],
+                    arguments.get("key_id")
+                )
+                return [TextContent(
+                    type="text",
+                    text=result
+                )]
+
             case GitTools.ADD:
                 result = git_add(repo, arguments["files"])
                 return [TextContent(
@@ -400,7 +435,7 @@ async def call_tool(name: str, arguments: dict) -> list[TextContent]:
             # Update the LOG case:
             case GitTools.LOG:
                 log = git_log(
-                    repo, 
+                    repo,
                     arguments.get("max_count", 10),
                     arguments.get("start_timestamp"),
                     arguments.get("end_timestamp")
@@ -409,7 +444,7 @@ async def call_tool(name: str, arguments: dict) -> list[TextContent]:
                     type="text",
                     text="Commit history:\n" + "\n".join(log)
                 )]
-            
+
             case GitTools.CREATE_BRANCH:
                 result = git_create_branch(
                     repo,
@@ -446,7 +481,7 @@ async def call_tool(name: str, arguments: dict) -> list[TextContent]:
                     type="text",
                     text=result
                 )]
-            
+
             case _:
                 raise ValueError(f"Unknown tool: {name}")
 

src/git/tests/test_server.py

@@ -1,7 +1,7 @@
 import pytest
 from pathlib import Path
 import git
-from mcp_server_git.server import git_checkout, git_branch, git_add, git_status
+from mcp_server_git.server import git_checkout, git_branch, git_add, git_status, git_commit_signed
 import shutil
 
 @pytest.fixture
@@ -97,3 +97,42 @@ def test_git_status(test_repository):
 
     assert result is not None
     assert "On branch" in result or "branch" in result.lower()
+
+def test_git_commit_signed_without_key_id(test_repository):
+    # Create and stage a new file
+    file_path = Path(test_repository.working_dir) / "signed_test.txt"
+    file_path.write_text("testing signed commit")
+    test_repository.index.add(["signed_test.txt"])
+
+    # Note: This test may fail if GPG is not configured on the system
+    # In that case, it should raise a GitCommandError
+    try:
+        result = git_commit_signed(test_repository, "Test signed commit")
+        assert "Changes committed and signed successfully" in result
+        assert "with hash" in result
+
+        # Verify the commit was actually created
+        latest_commit = test_repository.head.commit
+        assert latest_commit.message.strip() == "Test signed commit"
+    except git.GitCommandError as e:
+        # GPG not configured or signing failed - this is expected in CI/test environments
+        pytest.skip(f"GPG signing not available: {str(e)}")
+
+def test_git_commit_signed_with_key_id(test_repository):
+    # Create and stage a new file
+    file_path = Path(test_repository.working_dir) / "signed_test_with_key.txt"
+    file_path.write_text("testing signed commit with key")
+    test_repository.index.add(["signed_test_with_key.txt"])
+
+    # Note: This test may fail if GPG is not configured or key doesn't exist
+    try:
+        result = git_commit_signed(test_repository, "Test signed commit with key", "TESTKEY123")
+        assert "Changes committed and signed successfully" in result
+        assert "with hash" in result
+
+        # Verify the commit was actually created
+        latest_commit = test_repository.head.commit
+        assert latest_commit.message.strip() == "Test signed commit with key"
+    except git.GitCommandError as e:
+        # GPG not configured, key not found, or signing failed - expected in CI/test environments
+        pytest.skip(f"GPG signing with specific key not available: {str(e)}")