Chapter 7: Examples, Language Patterns, and Distribution Readiness

Welcome to Chapter 7: Examples, Language Patterns, and Distribution Readiness. 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 translates specification guidance into practical implementation templates.

Learning Goals

• evaluate official examples for runtime and structure decisions
• understand development vs production readiness boundaries
• map example patterns to your own server architecture
• prioritize distribution hardening before publishing bundles

Example Guidance

• use hello-world examples to validate toolchain and host install loop first.
• treat example projects as reference patterns, not production blueprints.
• add your own observability, secret management, and update policies before release.

Source References

• MCPB Examples
• Hello World UV Example

Summary

You now have an example-driven framework for taking bundles from prototype to hardened distribution.

Next: Chapter 8: Release, Governance, and Ecosystem Operations

Source Code Walkthrough

src/shared/config.ts

The getMcpConfigForManifest function in src/shared/config.ts handles a key part of this chapter's functionality:

}

export async function getMcpConfigForManifest(
  options: GetMcpConfigForManifestOptions,
): Promise<McpbManifestAny["server"]["mcp_config"] | undefined> {
  const {
    manifest,
    extensionPath,
    systemDirs,
    userConfig,
    pathSeparator,
    logger,
  } = options;
  const baseConfig = manifest.server?.mcp_config;
  if (!baseConfig) {
    return undefined;
  }

  let result: McpbManifestAny["server"]["mcp_config"] = {
    ...baseConfig,
  };

  if (baseConfig.platform_overrides) {
    if (process.platform in baseConfig.platform_overrides) {
      const platformConfig = baseConfig.platform_overrides[process.platform];

      result.command = platformConfig.command || result.command;
      result.args = platformConfig.args || result.args;
      result.env = platformConfig.env || result.env;
    }
  }

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/shared/config.ts

The isInvalidSingleValue function in src/shared/config.ts handles a key part of this chapter's functionality:

}

function isInvalidSingleValue(value: unknown): boolean {
  return value === undefined || value === null || value === "";
}

/**
 * Check if an extension has missing required configuration
 * @param manifest The extension manifest
 * @param userConfig The user configuration
 * @returns true if required configuration is missing
 */
export function hasRequiredConfigMissing({
  manifest,
  userConfig,
}: HasRequiredConfigMissingOptions): boolean {
  if (!manifest.user_config) {
    return false;
  }

  const config = userConfig || {};

  for (const [key, configOption] of Object.entries(manifest.user_config)) {
    if (configOption.required) {
      const value = config[key];
      if (
        isInvalidSingleValue(value) ||
        (Array.isArray(value) &&
          (value.length === 0 || value.some(isInvalidSingleValue)))
      ) {
        return true;
      }

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/shared/config.ts

The hasRequiredConfigMissing function in src/shared/config.ts handles a key part of this chapter's functionality:

  // Check if required configuration is missing
  if (hasRequiredConfigMissing({ manifest, userConfig })) {
    logger?.warn(
      `Extension ${manifest.name} has missing required configuration, skipping MCP config`,
    );
    return undefined;
  }

  const variables: Record<string, string | string[]> = {
    __dirname: extensionPath,
    pathSeparator,
    "/": pathSeparator,
    ...systemDirs,
  };

  // Build merged configuration from defaults and user settings
  const mergedConfig: Record<string, unknown> = {};

  // First, add defaults from manifest
  if (manifest.user_config) {
    for (const [key, configOption] of Object.entries(manifest.user_config)) {
      if (configOption.default !== undefined) {
        mergedConfig[key] = configOption.default;
      }
    }
  }

  // Then, override with user settings
  if (userConfig) {
    Object.assign(mergedConfig, userConfig);
  }

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/shared/config.ts

The GetMcpConfigForManifestOptions interface in src/shared/config.ts handles a key part of this chapter's functionality:

}

interface GetMcpConfigForManifestOptions {
  manifest: McpbManifestAny;
  extensionPath: string;
  systemDirs: Record<string, string>;
  userConfig: z.infer<typeof McpbUserConfigValuesSchema>;
  pathSeparator: string;
  logger?: Logger;
}

export async function getMcpConfigForManifest(
  options: GetMcpConfigForManifestOptions,
): Promise<McpbManifestAny["server"]["mcp_config"] | undefined> {
  const {
    manifest,
    extensionPath,
    systemDirs,
    userConfig,
    pathSeparator,
    logger,
  } = options;
  const baseConfig = manifest.server?.mcp_config;
  if (!baseConfig) {
    return undefined;
  }

  let result: McpbManifestAny["server"]["mcp_config"] = {
    ...baseConfig,
  };

  if (baseConfig.platform_overrides) {

This interface 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[getMcpConfigForManifest]
    B[isInvalidSingleValue]
    C[hasRequiredConfigMissing]
    D[GetMcpConfigForManifestOptions]
    E[HasRequiredConfigMissingOptions]
    A --> B
    B --> C
    C --> D
    D --> E