Make the MCP server port configurable via a flag in the dev command

packages/cli-v3/src/commands/dev.ts

@@ -21,6 +21,7 @@ const DevCommandOptions = CommonCommandOptions.extend({
   keepTmpFiles: z.boolean().default(false),
   maxConcurrentRuns: z.coerce.number().optional(),
   mcp: z.boolean().default(false),
+  mcpPort: z.coerce.number().optional().default(3333),
 });
 
 export type DevCommandOptions = z.infer<typeof DevCommandOptions>;
@@ -50,7 +51,8 @@ export function configureDevCommand(program: Command) {
         "Keep temporary files after the dev session ends, helpful for debugging"
       )
       // TODO: add a more detailed description, maybe a pointer to the docs on how to use MCP
-      .option("--mcp", "Run an MCP server")
+      .option("--mcp", "Start the MCP server")
+      .option("--mcp-port", "The port to run the MCP server on", "3333")
   ).action(async (options) => {
     wrapCommandAction("dev", DevCommandOptions, options, async (opts) => {
       await devCommand(opts);

packages/cli-v3/src/dev/devSession.ts

@@ -62,6 +62,7 @@ export async function startDevSession({
 
   if (rawArgs.mcp) {
     await startMcpServer({
+      port: rawArgs.mcpPort,
       cliApiClient: client,
       devSession: {
         dashboardUrl,

packages/cli-v3/src/dev/mcpServer.ts

@@ -145,6 +145,7 @@ app.post("/messages", (req, res) => {
 });
 
 export const startMcpServer = async (options: {
+  port: number;
   cliApiClient: CliApiClient;
   devSession: {
     dashboardUrl: string;
@@ -162,9 +163,7 @@ export const startMcpServer = async (options: {
   projectRef = options.devSession.projectRef;
   dashboardUrl = options.devSession.dashboardUrl;
 
-  // TODO: make the port configurable
-  const port = 3333;
-  app.listen(port, () => {
-    logger.info(`Trigger.dev MCP Server is now running on port ${port} ✨`);
+  app.listen(options.port, () => {
+    logger.info(`Trigger.dev MCP Server is now running on port ${options.port} ✨`);
   });
 };