mcp-development

# MCP Development ## MCP Server with Tools ```typescript import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js"; import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js"; import { z } from "zod"; const server = new McpServer({ name: "project-tools", version: "1.0.0", }); server.tool( "search_files", "Search for files matching a glob pattern in the project directory", { pattern: z.string().describe("Glob pattern (e.g., '**/*.ts')"), directory: z.string().optional().describe("Base directory to search from"), }, async ({ pattern, directory }) => { const files = await glob(pattern, { cwd: directory ?? process.cwd() }); return { content: [ { type: "text", text: files.length > 0 ? files.join("\n") : `No files found matching ${pattern}`, }, ], }; } ); server.tool( "run_query", "Execute a read-only SQL query against the application database", { query: z.string().describe("SQL SELECT query to execute"), limit: z.number().default(100).describe("Maximum rows to return"), }, async ({ query, limit }) => { if (!query.trim().toUpperCase().startsWith("SELECT")) { return { content: [{ type: "text", text: "Only SELECT queries are allowed" }], isError: true, }; } const rows = await db.query(`${query} LIMIT ${limit}`); return { content: [{ type: "text", text: JSON.stringify(rows, null, 2) }], }; } ); ``` ## Resources ```typescript server.resource( "schema", "db://schema", "Current database schema with all tables, columns, and relationships", async () => { const schema = await db.query(` SELECT table_name, column_name, data_type, is_nullable FROM information_schema.columns WHERE table_schema = 'public' ORDER BY table_name, ordinal_position `); return { contents: [ { uri: "db://schema", mimeType: "application/json", text: JSON.stringify(schema, null, 2), }, ], }; } ); server.resource( "config", "config://app", "Application configuration (secrets redacted)", async () => { const config = await loadConfig(); const safe = redactSecrets(config); return { contents: [ { uri: "config://app", mimeType: "application/json", text: JSON.stringify(safe, null, 2), }, ], }; } ); ``` ## Prompt Templates ```typescript server.prompt( "review-code", "Review code changes for bugs, security issues, and style", { diff: z.string().describe("Git diff or code to review"), focus: z.enum(["security", "performance", "style", "all"]).default("all"), }, async ({ diff, focus }) => ({ messages: [ { role: "user", content: { type: "text", text: `Review this code diff. Focus: ${focus}\n\n${diff}`, }, }, ], }) ); ``` ## Client Configuration ```json { "mcpServers": { "project-tools": { "command": "node", "args": ["./mcp-server/dist/index.js"], "env": { "DATABASE_URL": "postgres://localhost:5432/app" } }, "remote-server": { "url": "https://mcp.example.com/sse", "headers": { "Authorization": "Bearer ${MCP_TOKEN}" } } } } ``` ## Transport Setup ```typescript import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js"; const transport = new StdioServerTransport(); await server.connect(transport); ``` For HTTP-based servers, use the SSE transport for streaming responses to clients. ## Anti-Patterns - Creating tools with vague descriptions that don't explain when to use them - Not validating inputs with Zod schemas before processing - Returning raw error stack traces to the client - Missing `isError: true` flag on error responses - Creating too many fine-grained tools instead of composable ones - Not redacting secrets in resource responses ## Checklist - [ ] Each tool has a clear description explaining when and why to use it - [ ] Input parameters validated with Zod schemas and descriptive messages - [ ] Error responses include `isError: true` with user-friendly messages - [ ] Resources expose read-only data with secrets redacted - [ ] Prompt templates provide structured starting points for common tasks - [ ] Server handles graceful shutdown on SIGINT/SIGTERM - [ ] Tools are composable (do one thing well) rather than monolithic - [ ] Client configuration documented with required environment variables ## Diff History - **v00.33.0**: Ingested from awesome-claude-code-toolkit --- ## Why This Skill Exists Use — MCP server development including tool design, resource endpoints, prompt templates, and transport configuration <!-- SR_40: auto-generated from frontmatter `purpose`/`description` (OPP-Phase3). Expand with domain-specific rationale. --> ## When to Use Use this skill when the task requires mcp development capabilities. <!-- SR_40: auto-generated from frontmatter `when`/`description` (OPP-Phase3). --> ## What If Fails - condition: Código não disponível para análise <!-- SR_40: auto-generated from frontmatter `what_if_fails` (OPP-Phase3). -->