Git Prompts MCP Server

Instructions

Implementation Reference

• src/git_prompts_mcp_server/server.py:390-396 (registration)

  Registration of the 'git-cached-diff' tool using FastMCP's @APP.tool decorator, linking to the handler.

  @APP.tool(
      name="git-cached-diff",
      description="Get a diff between the files in the staging area (the index) and the HEAD",
  )
  async def git_cached_diff_tool() -> list[dict[str, str]]:
      return await GIT_METHOD_COLLETION.get_cached_diff_data()

• src/git_prompts_mcp_server/server.py:120-122 (handler)

  Core handler method in GitMethodCollection that executes the git-cached-diff logic: computes staged changes diff (HEAD vs index).

  async def get_cached_diff_data(self) -> list[dict[str, str]]:
      diff_results = _get_diff_results(self.repo.head.commit, None, self.excludes)
      return _get_diff_results_as_list_of_dict(diff_results)

• src/git_prompts_mcp_server/server.py:82-98 (helper)

  Helper function to retrieve and filter git diff results between commits or index.

  def _get_diff_results(
      source_commit: git.Commit, target_commit: git.Commit | None, excludes: list[str]
  ) -> list[git.Diff]:
      if target_commit is None:
          # Note: source_commit.diff() compares source with the index (staged changes)
          #       source_commit.diff(None) compares source with the working tree
          diff_results = source_commit.diff(create_patch=True)
      else:
          diff_results = source_commit.diff(target_commit, create_patch=True)
  
      for exclude_pattern in excludes:
          diff_results = [
              item
              for item in diff_results
              if not fnmatch(item.a_path or "", exclude_pattern) and not fnmatch(item.b_path or "", exclude_pattern)
          ]
      return diff_results

• src/git_prompts_mcp_server/server.py:34-42 (helper)

  Helper to convert git diff results to structured list of dictionaries for output.

  def _get_diff_results_as_list_of_dict(diff_results: list[git.Diff]) -> list[dict[str, str]]:
      return [
          {
              "a_path": item.a_path or "New Addition",
              "b_path": item.b_path or "Deleted",
              "diff": cast(bytes, item.diff).decode("utf-8"),
          }
          for item in diff_results
      ]