diff --git a/src/promptforge/core/git_manager.py b/src/promptforge/core/git_manager.py
index c5e49fc..f49c758 100644
--- a/src/promptforge/core/git_manager.py
+++ b/src/promptforge/core/git_manager.py
@@ -1,5 +1,7 @@
+"""Git integration for prompt version control."""
+
 from pathlib import Path
-from typing import List, Optional
+from typing import Any, List, Optional
 from datetime import datetime
 
 from git import Repo, Commit, GitCommandError
@@ -8,11 +10,23 @@ from .exceptions import GitError
 
 
 class GitManager:
+    """Manage git operations for prompt directories."""
+
     def __init__(self, prompts_dir: Path):
+        """Initialize git manager for a prompts directory.
+
+        Args:
+            prompts_dir: Path to the prompts directory.
+        """
         self.prompts_dir = Path(prompts_dir)
         self.repo: Optional[Repo] = None
 
     def init(self) -> bool:
+        """Initialize a git repository in the prompts directory.
+
+        Returns:
+            True if repository was created, False if it already exists.
+        """
         try:
             if not self.prompts_dir.exists():
                 self.prompts_dir.mkdir(parents=True, exist_ok=True)
@@ -28,6 +42,7 @@ class GitManager:
             raise GitError(f"Failed to initialize git repository: {e}")
 
     def _is_git_repo(self) -> bool:
+        """Check if prompts_dir is a git repository."""
         try:
             self.repo = Repo(str(self.prompts_dir))
             return not self.repo.bare
@@ -35,53 +50,140 @@ class GitManager:
             return False
 
     def _configure_gitignore(self) -> None:
+        """Create .gitignore for prompts directory."""
         gitignore_path = self.prompts_dir / ".gitignore"
         if not gitignore_path.exists():
-            gitignore_path.write_text("*.lock\n.temp*\n")
+            gitignore_path.write_text("*.lock\\.temp*\\n")
 
     def commit(self, message: str, author: Optional[str] = None) -> Commit:
+        """Commit all changes to prompts.
+
+        Args:
+            message: Commit message.
+            author: Author string (e.g., "Name <email>").
+
+        Returns:
+            Created commit object.
+
+        Raises:
+            GitError: If commit fails.
+        """
         self._ensure_repo()
+        assert self.repo is not None
         try:
             self.repo.index.add(["*"])
-            return self.repo.index.commit(message, author=author)
+            author_arg: Any = author  # type: ignore[assignment]
+            return self.repo.index.commit(message, author=author_arg)
         except GitCommandError as e:
             raise GitError(f"Failed to commit changes: {e}")
 
     def log(self, max_count: int = 20) -> List[Commit]:
+        """Get commit history.
+
+        Args:
+            max_count: Maximum number of commits to return.
+
+        Returns:
+            List of commit objects.
+        """
         self._ensure_repo()
+        assert self.repo is not None
         try:
             return list(self.repo.iter_commits(max_count=max_count))
         except GitCommandError as e:
             raise GitError(f"Failed to get commit log: {e}")
 
-    def create_branch(self, branch_name: str) -> None:
+    def show_commit(self, commit_sha: str) -> str:
+        """Show content of a specific commit.
+
+        Args:
+            commit_sha: SHA of the commit.
+
+        Returns:
+            Commit diff as string.
+        """
         self._ensure_repo()
+        assert self.repo is not None
+        try:
+            commit = self.repo.commit(commit_sha)
+            diff_result = commit.diff("HEAD~1" if commit_sha == "HEAD" else f"{commit_sha}^")
+            return str(diff_result) if diff_result else ""
+        except Exception as e:
+            raise GitError(f"Failed to show commit: {e}")
+
+    def create_branch(self, branch_name: str) -> None:
+        """Create a new branch for prompt variations.
+
+        Args:
+            branch_name: Name of the new branch.
+
+        Raises:
+            GitError: If branch creation fails.
+        """
+        self._ensure_repo()
+        assert self.repo is not None
         try:
             self.repo.create_head(branch_name)
         except GitCommandError as e:
             raise GitError(f"Failed to create branch: {e}")
 
     def switch_branch(self, branch_name: str) -> None:
+        """Switch to a different branch.
+
+        Args:
+            branch_name: Name of the branch to switch to.
+
+        Raises:
+            GitError: If branch switch fails.
+        """
         self._ensure_repo()
+        assert self.repo is not None
         try:
             self.repo.heads[branch_name].checkout()
         except GitCommandError as e:
             raise GitError(f"Failed to switch branch: {e}")
 
     def list_branches(self) -> List[str]:
+        """List all branches.
+
+        Returns:
+            List of branch names.
+        """
         self._ensure_repo()
+        assert self.repo is not None
         return [head.name for head in self.repo.heads]
 
     def status(self) -> str:
+        """Get git status.
+
+        Returns:
+            Status string.
+        """
         self._ensure_repo()
+        assert self.repo is not None
         return self.repo.git.status()
 
     def diff(self) -> str:
+        """Show uncommitted changes.
+
+        Returns:
+            Diff as string.
+        """
         self._ensure_repo()
+        assert self.repo is not None
         return self.repo.git.diff()
 
     def get_file_history(self, filename: str) -> List[dict]:
+        """Get commit history for a specific file.
+
+        Args:
+            filename: Name of the file.
+
+        Returns:
+            List of commit info dictionaries.
+        """
         self._ensure_repo()
+        assert self.repo is not None
         commits = []
         try:
             for commit in self.repo.iter_commits("--all", filename):
@@ -96,6 +198,7 @@ class GitManager:
         return commits
 
     def _ensure_repo(self) -> None:
+        """Ensure repository is initialized."""
         if self.repo is None:
             if not self._is_git_repo():
-                raise GitError("Git repository not initialized. Run 'pf init' first.")
\ No newline at end of file
+                raise GitError("Git repository not initialized. Run 'pf init' first.")