MCP Character Count

Instructions

Count the length of input text.

- mode="chars": Unicode code points count (Python len).
- mode="bytes": UTF-8 encoded byte length.
- include_whitespace: when False, whitespace characters are filtered out before counting.

Implementation Reference

• src/mcp_charcount/server.py:11-38 (handler)

  The core handler function for the 'count_chars' MCP tool, decorated with @mcp.tool() for automatic schema inference and registration. Implements logic to count characters or bytes, optionally excluding whitespace.

  @mcp.tool()
  def count_chars(
      text: str,
      mode: Mode = "chars",
      include_whitespace: bool = True,
  ) -> Dict[str, Any]:
      """
      Count the length of input text.
  
      - mode="chars": Unicode code points count (Python len).
      - mode="bytes": UTF-8 encoded byte length.
      - include_whitespace: when False, whitespace characters are filtered out before counting.
      """
  
      s = text if include_whitespace else "".join(ch for ch in text if not ch.isspace())
  
      if mode == "bytes":
          count = len(s.encode("utf-8"))
      elif mode == "chars":
          count = len(s)
      else:
          raise ValueError("Unsupported mode. Use 'chars' or 'bytes'.")
  
      return {
          "count": count,
          "mode": mode,
          "include_whitespace": include_whitespace,
      }

• src/mcp_charcount/server.py:8-8 (schema)

  Type alias defining the valid values for the 'mode' parameter in the count_chars tool schema.

  Mode = Literal["chars", "bytes"]

• src/mcp_charcount/server.py:11-11 (registration)

  Decorator registering the count_chars function as an MCP tool with name derived from function name and schema from type hints.

  @mcp.tool()