MCP Devcontainers

Instructions

Implementation Reference

• src/devcontainer.ts:38-43 (handler)

  Core handler function that runs the devcontainer 'up' command by calling the internal runCommand helper with appropriate arguments.

  export async function up(options: DevContainerUpOptions): Promise<number> {
    return runCommand(
      ['up', '--workspace-folder', options.workspaceFolder],
      createStdoutStream(options)
    );
  }

• src/devcontainer.ts:15-17 (schema)

  TypeScript interface defining the input parameters for the devcontainer up handler.

  interface DevContainerUpOptions extends DevcontainerOptions {
    workspaceFolder: string;
  }

• src/server.ts:10-30 (registration)

  MCP tool registration for 'devcontainer_up', including tool description, Zod input schema validation, and thin wrapper handler that calls the core up implementation.

  server.tool(
    "devcontainer_up",
    "Start or initialize a devcontainer environment in the specified workspace folder." + 
    "Use this to ensure the devcontainer is running and ready for development tasks.",
    {
      workspaceFolder: z.string(),
      outputFilePath: z.string().optional(),
    },
    async ({ workspaceFolder, outputFilePath }) => {
      await devcontainers.up({ workspaceFolder, stdioFilePath: outputFilePath });
  
      return {
        content: [
          {
            type: "text",
            text: `Devcontainer started in ${workspaceFolder}`,
          }
        ]
      }
    }
  );

• src/devcontainer.ts:65-83 (helper)

  Internal helper that spawns the Node.js process for the devcontainer CLI binary, pipes stdout, and resolves/rejects based on exit code.

  async function runCommand(args: string[], stdout: fs.WriteStream): Promise<number> {
    return new Promise((resolve, reject) => {
      const proc = spawn('node', [devcontainerBinaryPath(), ...args], {
        stdio: ['ignore', 'pipe', 'inherit'],
      });
  
      proc.stdout.pipe(stdout);
  
      proc.on('close', (code) => {
        stdout.end();
  
        if (code === 0) {
          resolve(code);
        } else {
          reject(new Error(`devcontainer command ${args.join(' ')} exited with code ${code}`));
        }
      });
    });
  }

• src/devcontainer.ts:85-90 (helper)

  Helper function to create a write stream for stdout, either to a file or /dev/null.

  function createStdoutStream(options: DevcontainerOptions): fs.WriteStream {
    if (!options.stdioFilePath)
      return fs.createWriteStream('/dev/null', { flags: 'w' })
    
    return fs.createWriteStream(options.stdioFilePath, { flags: 'w' });
  }