Function handleExecMessage

src/proxy.ts:937–1091

(
  execMsg: ExecServerMessage,
  mcpTools: McpToolDefinition[],
  sendFrame: (data: Uint8Array) => void,
  onMcpExec: (exec: PendingExec) => void,
)

}

function handleExecMessage(
  execMsg: ExecServerMessage,
  mcpTools: McpToolDefinition[],
  sendFrame: (data: Uint8Array) => void,
  onMcpExec: (exec: PendingExec) => void,
): void {
  const execCase = execMsg.message.case;

  if (execCase === "requestContextArgs") {
    const requestContext = create(RequestContextSchema, {
      rules: [],
      repositoryInfo: [],
      tools: mcpTools,
      gitRepos: [],
      projectLayouts: [],
      mcpInstructions: [],
      fileContents: {},
      customSubagents: [],
    });
    const result = create(RequestContextResultSchema, {
      result: {
        case: "success",
        value: create(RequestContextSuccessSchema, { requestContext }),
      },
    });
    sendExecResult(execMsg, "requestContextResult", result, sendFrame);
    return;
  }

  if (execCase === "mcpArgs") {
    const mcpArgs = execMsg.message.value;
    const decoded = decodeMcpArgsMap(mcpArgs.args ?? {});
    onMcpExec({
      execId: execMsg.execId,
      execMsgId: execMsg.id,
      toolCallId: mcpArgs.toolCallId || crypto.randomUUID(),
      toolName: mcpArgs.toolName || mcpArgs.name,
      decodedArgs: JSON.stringify(decoded),
    });
    return;
  }

  // --- Reject native Cursor tools ---
  // The model tries these first. We must respond with rejection/error
  // so it falls back to our MCP tools (registered via RequestContext).
  const REJECT_REASON = "Tool not available in this environment. Use the MCP tools provided instead.";

  if (execCase === "readArgs") {
    const args = execMsg.message.value;
    const result = create(ReadResultSchema, {
      result: { case: "rejected", value: create(ReadRejectedSchema, { path: args.path, reason: REJECT_REASON }) },
    });
    sendExecResult(execMsg, "readResult", result, sendFrame);
    return;
  }
  if (execCase === "lsArgs") {
    const args = execMsg.message.value;
    const result = create(LsResultSchema, {