Lesson 29: Resources and Prompts

import {
  ListResourcesRequestSchema,
  ReadResourceRequestSchema,
} from "@modelcontextprotocol/sdk/types.js";
 
// Update server capabilities to include resources
const server = new Server(
  { name: "my-project-tools", version: "1.0.0" },
  { capabilities: { tools: {}, resources: {} } }
);
 
// List available resources
server.setRequestHandler(ListResourcesRequestSchema, async () => {
  return {
    resources: [
      {
        uri: "project://architecture",
        name: "Architecture Documentation",
        description: "High-level architecture overview of this project",
        mimeType: "text/plain",
      },
      {
        uri: "project://api-schema",
        name: "API Schema",
        description: "OpenAPI specification for the project's REST API",
        mimeType: "application/json",
      },
      {
        uri: "project://test-results/latest",
        name: "Latest Test Results",
        description: "Results from the most recent test run",
        mimeType: "text/plain",
      },
    ],
  };
});
 
// Read a specific resource
server.setRequestHandler(ReadResourceRequestSchema, async (request) => {
  const { uri } = request.params;
 
  if (uri === "project://architecture") {
    const archDoc = fs.readFileSync(
      path.join(PROJECT_ROOT, "docs/architecture.md"),
      "utf-8"
    );
    return {
      contents: [{ uri, mimeType: "text/plain", text: archDoc }],
    };
  }
 
  if (uri === "project://api-schema") {
    const schema = fs.readFileSync(
      path.join(PROJECT_ROOT, "openapi.json"),
      "utf-8"
    );
    return {
      contents: [{ uri, mimeType: "application/json", text: schema }],
    };
  }
 
  if (uri === "project://test-results/latest") {
    const resultsFile = path.join(PROJECT_ROOT, ".test-results/latest.txt");
    if (fs.existsSync(resultsFile)) {
      const results = fs.readFileSync(resultsFile, "utf-8");
      return { contents: [{ uri, mimeType: "text/plain", text: results }] };
    }
    return {
      contents: [{ uri, mimeType: "text/plain", text: "No test results found." }],
    };
  }
 
  throw new Error(`Unknown resource: ${uri}`);
});

import {
  ListPromptsRequestSchema,
  GetPromptRequestSchema,
} from "@modelcontextprotocol/sdk/types.js";
 
// Update capabilities
const server = new Server(
  { name: "my-project-tools", version: "1.0.0" },
  { capabilities: { tools: {}, resources: {}, prompts: {} } }
);
 
server.setRequestHandler(ListPromptsRequestSchema, async () => {
  return {
    prompts: [
      {
        name: "code_review",
        description: "Start a code review session for a specific file",
        arguments: [
          {
            name: "file_path",
            description: "Path to the file to review",
            required: true,
          },
          {
            name: "review_type",
            description: "Type of review: security, performance, or general",
            required: false,
          },
        ],
      },
      {
        name: "implement_feature",
        description: "Start a feature implementation session with standard workflow",
        arguments: [
          {
            name: "feature_description",
            description: "Description of the feature to implement",
            required: true,
          },
        ],
      },
    ],
  };
});
 
server.setRequestHandler(GetPromptRequestSchema, async (request) => {
  const { name, arguments: args } = request.params;
 
  if (name === "code_review") {
    const filePath = args?.file_path ?? "the specified file";
    const reviewType = args?.review_type ?? "general";
 
    return {
      description: `Code review session for ${filePath}`,
      messages: [
        {
          role: "user",
          content: {
            type: "text",
            text: `Please perform a ${reviewType} code review of ${filePath}.
 
For this review:
1. Read the file carefully
2. Run the linter if applicable
3. Check for:
   - ${reviewType === "security" ? "Input validation, injection vulnerabilities, authentication issues, secrets in code" : ""}
   - ${reviewType === "performance" ? "N+1 queries, unnecessary computation, blocking I/O, memory leaks" : ""}
   - ${reviewType === "general" ? "Correctness, error handling, readability, test coverage" : ""}
4. Write a structured review with specific line references
 
Begin when ready.`,
          },
        },
      ],
    };
  }
 
  if (name === "implement_feature") {
    const description = args?.feature_description ?? "the described feature";
    return {
      description: `Feature implementation: ${description}`,
      messages: [
        {
          role: "user",
          content: {
            type: "text",
            text: `Implement the following feature: ${description}
 
Follow this workflow:
1. Explore the relevant parts of the codebase
2. Propose an implementation plan (list files to create/modify)
3. Wait for confirmation before coding
4. Implement step by step, running tests after each major change
5. Ensure all tests pass before declaring done`,
          },
        },
      ],
    };
  }
 
  throw new Error(`Unknown prompt: ${name}`);
});