🦨 MCP SDK Developer Guide: Code Like It’s 10,000 B.C.

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🦴 What Is MCP SDK?

You are a primitive developer. The world is cold. You must survive.

MCP SDK is your flint and fire — a Dart package that lets you build AI-powered servers using:

• Tools – Actions the AI can perform (like hitting things with a big rock)
• Prompts – Phrases the AI repeats (tribal chants, but for output)
• Resources – Data and files the AI can read (cave drawings)

You’re not writing software. You’re building the first digital tribe. And MCP is the torch.

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🔨 Why Expose Tools, Prompts, and Resources?

Tools – "AI, go do thing."

• Think: API endpoints, but with more grunting.
• You give the AI a function it can call, like:
  • Checking if a Dart package exists
  • Querying a database
  • Running some logic
  • Controlling a thing that beeps

Example: You build FireLookup — a tool that looks into the smoke and checks pub.dev for signs of a Dart package.

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Prompts – "AI, talk like this."

• Think: pre-written speech scrolls, but passed around the fire.
• You give the AI a tone or task:
  • Be a code reviewer
  • Answer customer support
  • Start a story
  • Fill in structured info

Example: Use CodeCritic, a prompt that reviews your code like a cranky cave elder who hates tabs.

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Resources – "AI, go read wall."

• Think: shared files, but they’re sacred cave scribbles.
• AI can inspect:
  • Source code
  • Docs
  • Images or audio
  • Database schemas

Example: Expose your project files so the AI can make suggestions or just stare in horror at your main.dart.

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🛠️ How MCP SDK Helps You Not Die

You don’t need to handcraft JSON spells or chant schemas into the void.
Just:

1. Annotate Dart classes with @McpTool, @McpPrompt
2. Implement execute() – the action or response
3. Run code gen with build_runner (like automated mammoth hunting)
4. Register with your server – add it to the tribal knowledge

The SDK will:

• Serialize data (grunts → symbols)
• Generate schemas (ritual circles)
• Register handlers (tribal assignments)
• Dispatch calls (yell and stuff happens)

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🔥 FireLookup: When You Need to Know if the Package is Real

@McpTool(
  name: 'check_pub_package',
  description: 'Peers into pub.dev to check if a Dart package exists and its latest version.',
)
@JsonSerializable()
class CheckPubPackageArgs {
  @McpToolArg(description: 'Package name', required: true)
  final String packageName;

  const CheckPubPackageArgs({required this.packageName});

  factory CheckPubPackageArgs.fromJson(Map<String, dynamic> json) =>
      _$CheckPubPackageArgsFromJson(json);

  Map<String, dynamic> toJson() => _$CheckPubPackageArgsToJson(this);

  // This is the part where we poke the fire and hope it talks back.
  FutureOr<CallToolResult> execute() async {
    final info = await fetchPubPackageInfo(packageName);
    if (info == null) {
      return CallToolResult(content: [
        TextContent(text: '🔥 No fire. "$packageName" not found on pub.dev.')
      ], isError: true);
    }
    return CallToolResult(content: [
      TextContent(text: '🔥 Fire shows "$packageName". Latest version: \${info.version}')
    ]);
  }
}

Register it:

server.registerCheckPubPackageTool(); // You may grunt here if necessary.

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🧓 CodeCritic: The Village Elder Who Judges All Code

@McpPrompt(
  name: 'code_review_spell',
  description: 'An old village coder reviews your code.',
)
@JsonSerializable()
class CodeReviewSpellArgs {
  @McpPromptArg(description: 'Code snippet', required: true)
  final String code;

  const CodeReviewSpellArgs({required this.code});

  factory CodeReviewSpellArgs.fromJson(Map<String, dynamic> json) =>
      _$CodeReviewSpellArgsFromJson(json);

  Map<String, dynamic> toJson() => _$CodeReviewSpellArgsToJson(this);

  FutureOr<GetPromptResult> execute() {
    return GetPromptResult(messages: [
      PromptMessage(
        role: PromptMessageRole.user,
        content: TextContent(
          text: '🧓 CodeCritic speaks:\n"This code:\n\$code\n...it weak. Needs more strength. Use less fire, more logic."',
        ),
      )
    ]);
  }
}

Register the wisdom:

server.registerCodeReviewSpellPrompt();

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🩵 Resources: Let AI Read the Cave Wall

• Implement a resource provider
• Share file URIs like file:///path/to/fossil.dart
• AI can:
  • List files
  • Read them
  • Subscribe to changes (magic smoke updates)

Use Case: AI can now peek at your source code, and maybe suggest a better wheel.

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🏡 Setup: Tell the Tribe What You Can Do

final serverCapabilities = ServerCapabilities(
  tools: ServerCapabilitiesTools(listChanged: true),
  prompts: ServerCapabilitiesPrompts(listChanged: true),
  resources: ServerCapabilitiesResources(listChanged: true, subscribe: true),
);

You now have a fire pit. You now have knowledge.
You are ready to build.

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🐾 Summary: For the Hunter Who Reads No Scrolls

• MCP SDK turns Dart code into AI-callable things
• FireLookup is your package-checking tool
• CodeCritic is your reusable grump prompt
• Resources are your files, for AI to scan like ancient runes
• Minimal setup: Annotate → Implement → Generate → Register → Profit? Probably not.

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Now go, cave coder. Bang rocks together until your server hums. Then teach the AI to do it better.