Obsidian MCP Server

Instructions

Implementation Reference

• src/obsidian_mcp/server.py:569-610 (handler)

  MCP tool handler for 'create_note'. Registers the tool and implements the logic by calling the vault's create_note method, including input validation and frontmatter handling for tags.

  @mcp.tool(name="create_note", description="Create a new note in the vault")
  def create_note(
      path: str, content: str, tags: list[str] | None = None, overwrite: bool = False
  ) -> str:
      """
      Create a new note.
  
      Args:
          path: Relative path for the new note (e.g., "Projects/New Idea.md")
          content: Content of the note
          tags: Optional list of tags to add to frontmatter
          overwrite: If true, overwrite existing note
  
      Returns:
          Success message
      """
      if not path or not path.strip():
          return "Error: Path cannot be empty"
      if len(path) > 1000:
          return "Error: Path too long"
      if len(content) > 1_000_000:
          return "Error: Content too large (max 1MB)"
  
      context = _get_context()
  
      try:
          # Build frontmatter if tags provided
          frontmatter = None
          if tags:
              frontmatter = {"tags": tags}
  
          context.vault.create_note(path, content, frontmatter, overwrite)
          return f"✓ Created note: {path}"
  
      except FileExistsError:
          return f"Error: Note already exists: {path} (use overwrite=true to replace)"
      except VaultSecurityError as e:
          return f"Error: Security violation: {e}"
      except Exception as e:
          logger.exception(f"Error creating note {path}")
          return f"Error creating note: {e}"

• src/obsidian_mcp/vault.py:470-511 (helper)

  Core implementation in ObsidianVault class that creates the note file, handles frontmatter insertion, directory creation, and security validation.

  def create_note(
      self,
      relative_path: str,
      content: str,
      frontmatter: dict[str, Any] | None = None,
      overwrite: bool = False,
  ) -> None:
      """
      Create a new note in the vault.
  
      Args:
          relative_path: Path where to create the note
          content: Content of the note
          frontmatter: Optional frontmatter dict
          overwrite: If True, overwrite existing file
  
      Raises:
          VaultSecurityError: If path is invalid
          FileExistsError: If note already exists and overwrite=False
      """
      file_path = self._validate_path(relative_path)
  
      # Check if already exists
      if file_path.exists() and not overwrite:
          raise FileExistsError(f"Note already exists: {relative_path}")
  
      # Ensure parent directory exists
      file_path.parent.mkdir(parents=True, exist_ok=True)
  
      # Build full content with frontmatter
      full_content = ""
      if frontmatter:
          full_content = "---\n"
          full_content += yaml.dump(frontmatter, default_flow_style=False, sort_keys=False)
          full_content += "---\n"
  
      full_content += content
  
      # Write file
      file_path.write_text(full_content, encoding="utf-8")
      logger.info(f"Created note: {relative_path}")

• src/obsidian_mcp/server.py:569-610 (registration)

  The @mcp.tool decorator registers the 'create_note' tool with FastMCP, defining its name, description, and input schema from function signature.

  @mcp.tool(name="create_note", description="Create a new note in the vault")
  def create_note(
      path: str, content: str, tags: list[str] | None = None, overwrite: bool = False
  ) -> str:
      """
      Create a new note.
  
      Args:
          path: Relative path for the new note (e.g., "Projects/New Idea.md")
          content: Content of the note
          tags: Optional list of tags to add to frontmatter
          overwrite: If true, overwrite existing note
  
      Returns:
          Success message
      """
      if not path or not path.strip():
          return "Error: Path cannot be empty"
      if len(path) > 1000:
          return "Error: Path too long"
      if len(content) > 1_000_000:
          return "Error: Content too large (max 1MB)"
  
      context = _get_context()
  
      try:
          # Build frontmatter if tags provided
          frontmatter = None
          if tags:
              frontmatter = {"tags": tags}
  
          context.vault.create_note(path, content, frontmatter, overwrite)
          return f"✓ Created note: {path}"
  
      except FileExistsError:
          return f"Error: Note already exists: {path} (use overwrite=true to replace)"
      except VaultSecurityError as e:
          return f"Error: Security violation: {e}"
      except Exception as e:
          logger.exception(f"Error creating note {path}")
          return f"Error creating note: {e}"