Online Judge MCP Server

Instructions

Submit code to the Online Judge for a specific problem.
problem_id: the internal system ID of the problem.
language: string such as "C", "C++", "Python3".
code: the source code to submit.

Implementation Reference

• src/oj_mcp_server/server.py:69-82 (handler)

  MCP tool handler for submit_code - registered with @mcp.tool() decorator. This function receives problem_id, code, and language parameters, authenticates the client, calls the OJClient.submit_code method, and returns the result as a string.

  @mcp.tool()
  def submit_code(problem_id: int, code: str, language: str) -> str:
      """
      Submit code to the Online Judge for a specific problem.
      problem_id: the internal system ID of the problem.
      language: string such as "C", "C++", "Python3".
      code: the source code to submit.
      """
      c = get_authenticated_client()
      try:
          data = c.submit_code(code=code, language=language, problem_id=problem_id)
          return str(data)
      except Exception as e:
          return f"Error: {e}"

• src/oj_mcp_server/server.py:69-82 (registration)

  Tool registration point - the @mcp.tool() decorator on line 69 registers the submit_code function as an available MCP tool.

  @mcp.tool()
  def submit_code(problem_id: int, code: str, language: str) -> str:
      """
      Submit code to the Online Judge for a specific problem.
      problem_id: the internal system ID of the problem.
      language: string such as "C", "C++", "Python3".
      code: the source code to submit.
      """
      c = get_authenticated_client()
      try:
          data = c.submit_code(code=code, language=language, problem_id=problem_id)
          return str(data)
      except Exception as e:
          return f"Error: {e}"

• src/oj_mcp_server/oj_client.py:60-70 (handler)

  Core implementation of submit_code logic in OJClient class. Updates CSRF token, creates payload with code/language/problem_id, and makes a POST request to /api/submission endpoint on the Online Judge.

  def submit_code(self, code, language, problem_id):
      self._update_csrf_token()
      payload = {
          "code": code,
          "language": language,
          "problem_id": int(problem_id)
      }
      # OJ API expect form data for submission
      resp = self.session.post(self._get_url("/api/submission"), data=payload, timeout=15)
      resp.raise_for_status()
      return resp.json()