LibreSprite MCP

Instructions

Implementation Reference

• src/libresprite_mcp/mcp_server.py:28-42 (handler)

  MCP tool handler for 'run_script', decorated with @self.mcp.tool(), delegates to LibrespriteProxy.
  @self.mcp.tool() def run_script(script: str, ctx: Context) -> str: """ Run a JavaScript script inside Libresprite. IMPORTANT: Make sure you are well versed with the documentation and examples provided in the resources `docs:reference` and `docs:examples`. Args: script: The script to execute Returns: Console output """ return self._libresprite_proxy.run_script(script, ctx)
• src/libresprite_mcp/libresprite_proxy.py:93-124 (handler)

  Core logic of run_script in LibrespriteProxy: sets script on Flask endpoint, waits for output from remote JS, returns console output.
  def run_script(self, script: str, ctx: Context) -> str: """ Run a script in the execution context. WARNING: This method is synchronous and blocking. Args: script: The script to execute """ # This proxy only allows one script to be executed at a time if self._lock: ctx.error("Script execution is already in progress...") raise RuntimeError("Script execution is already in progress.") # Sending the script ctx.info("Sending script to libresprite...") self._lock = True self._script = script self._script_event.set() # Waiting for execution if not self._output_event.wait(timeout=15): ctx.warning("This is taking longer than usual, make sure the user has the Libresprite application with the remote script running?") self._output_event.wait() self._output_event.clear() # Return the output ctx.info("Script execution completed, checking the logs...") output = self._output self._output = None self._lock = False return output
• remote/mcp.js:249-259 (helper)

  Remote JS implementation: executes the received script using new Function, captures output via overridden console.log.
  function runScript(script) { if (!script) { return; } try { // Execute in global scope with our custom logger... new Function('console', script)(console); } catch (e) { console.log('Error in script:', e.message); } }
• src/libresprite_mcp/mcp_server.py:28-42 (registration)

  Registration of the 'run_script' tool via FastMCP decorator in _setup_tools method.
  @self.mcp.tool() def run_script(script: str, ctx: Context) -> str: """ Run a JavaScript script inside Libresprite. IMPORTANT: Make sure you are well versed with the documentation and examples provided in the resources `docs:reference` and `docs:examples`. Args: script: The script to execute Returns: Console output """ return self._libresprite_proxy.run_script(script, ctx)