Chapter 3: Server Configuration and Runtime Packaging

Welcome to Chapter 3: Server Configuration and Runtime Packaging. In this part of MCPB Tutorial: Packaging and Distributing Local MCP Servers as Bundles, you will build an intuitive mental model first, then move into concrete implementation details and practical production tradeoffs.

This chapter maps bundle runtime configuration to language-specific packaging realities.

Learning Goals

• configure server and mcp_config fields correctly
• choose between Node, Python, Binary, and UV runtime paths
• understand dependency bundling tradeoffs by runtime type
• reduce install/runtime failures across host environments

Runtime Strategy Matrix

Server Type	Practical Guidance
node	easiest cross-platform baseline for many hosts
python	requires careful dependency/runtime packaging
binary	strongest portability if statically linked
uv	experimental path with host-managed Python/deps

Source References

• MCPB README - Directory Structures
• Manifest Spec - Server Configuration
• Hello World UV Example

Summary

You now have a runtime packaging model for reliable MCPB installation and execution.

Next: Chapter 4: Tools, Prompts, User Config, and Localization

Source Code Walkthrough

src/cli/init.ts

The promptBasicInfo function in src/cli/init.ts handles a key part of this chapter's functionality:

}

export async function promptBasicInfo(
  packageData: PackageJson,
  resolvedPath: string,
) {
  const defaultName = packageData.name || basename(resolvedPath);

  const name = await input({
    message: "Extension name:",
    default: defaultName,
    validate: (value) => value.trim().length > 0 || "Name is required",
  });

  const authorName = await input({
    message: "Author name:",
    default: getDefaultAuthorName(packageData),
    validate: (value) => value.trim().length > 0 || "Author name is required",
  });

  const displayName = await input({
    message: "Display name (optional):",
    default: name,
  });

  const version = await input({
    message: "Version:",
    default: packageData.version || "1.0.0",
    validate: (value) => {
      if (!value.trim()) return "Version is required";
      if (!/^\d+\.\d+\.\d+/.test(value)) {
        return "Version must follow semantic versioning (e.g., 1.0.0)";

This function is important because it defines how MCPB Tutorial: Packaging and Distributing Local MCP Servers as Bundles implements the patterns covered in this chapter.

src/cli/init.ts

The promptAuthorInfo function in src/cli/init.ts handles a key part of this chapter's functionality:

}

export async function promptAuthorInfo(packageData: PackageJson) {
  const authorEmail = await input({
    message: "Author email (optional):",
    default: getDefaultAuthorEmail(packageData),
  });

  const authorUrl = await input({
    message: "Author URL (optional):",
    default: getDefaultAuthorUrl(packageData),
  });

  return { authorEmail, authorUrl };
}

export async function promptServerConfig(packageData?: PackageJson) {
  const serverType = (await select({
    message: "Server type:",
    choices: [
      { name: "Node.js", value: "node" },
      { name: "Python", value: "python" },
      { name: "Binary", value: "binary" },
    ],
    default: "node",
  })) as "node" | "python" | "binary";

  const entryPoint = await input({
    message: "Entry point:",
    default: getDefaultEntryPoint(serverType, packageData),
  });

This function is important because it defines how MCPB Tutorial: Packaging and Distributing Local MCP Servers as Bundles implements the patterns covered in this chapter.

src/cli/init.ts

The promptServerConfig function in src/cli/init.ts handles a key part of this chapter's functionality:

}

export async function promptServerConfig(packageData?: PackageJson) {
  const serverType = (await select({
    message: "Server type:",
    choices: [
      { name: "Node.js", value: "node" },
      { name: "Python", value: "python" },
      { name: "Binary", value: "binary" },
    ],
    default: "node",
  })) as "node" | "python" | "binary";

  const entryPoint = await input({
    message: "Entry point:",
    default: getDefaultEntryPoint(serverType, packageData),
  });

  const mcp_config = createMcpConfig(serverType, entryPoint);

  return { serverType, entryPoint, mcp_config };
}

export async function promptTools() {
  const addTools = await confirm({
    message:
      "Does your MCP Server provide tools you want to advertise (optional)?",
    default: true,
  });

  const tools: Array<{ name: string; description?: string }> = [];
  let toolsGenerated = false;

This function is important because it defines how MCPB Tutorial: Packaging and Distributing Local MCP Servers as Bundles implements the patterns covered in this chapter.

src/cli/init.ts

The promptTools function in src/cli/init.ts handles a key part of this chapter's functionality:

}

export async function promptTools() {
  const addTools = await confirm({
    message:
      "Does your MCP Server provide tools you want to advertise (optional)?",
    default: true,
  });

  const tools: Array<{ name: string; description?: string }> = [];
  let toolsGenerated = false;

  if (addTools) {
    let addMore = true;
    while (addMore) {
      const toolName = await input({
        message: "Tool name:",
        validate: (value) => value.trim().length > 0 || "Tool name is required",
      });
      const toolDescription = await input({
        message: "Tool description (optional):",
      });

      tools.push({
        name: toolName,
        ...(toolDescription ? { description: toolDescription } : {}),
      });

      addMore = await confirm({
        message: "Add another tool?",
        default: false,
      });

This function is important because it defines how MCPB Tutorial: Packaging and Distributing Local MCP Servers as Bundles implements the patterns covered in this chapter.

How These Components Connect

flowchart TD
    A[promptBasicInfo]
    B[promptAuthorInfo]
    C[promptServerConfig]
    D[promptTools]
    E[promptPrompts]
    A --> B
    B --> C
    C --> D
    D --> E