mirror of
https://github.com/coleam00/context-engineering-intro.git
synced 2025-12-29 16:14:56 +00:00
MCP Server Example with PRPs
This commit is contained in:
Cole Medin
235
use-cases/mcp-server/examples/database-tools-sentry.ts
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235
use-cases/mcp-server/examples/database-tools-sentry.ts
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@@ -0,0 +1,235 @@
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import * as Sentry from "@sentry/cloudflare";
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import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
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import {
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Props,
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ListTablesSchema,
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QueryDatabaseSchema,
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ExecuteDatabaseSchema,
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createErrorResponse,
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createSuccessResponse
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} from "../types";
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import { validateSqlQuery, isWriteOperation, formatDatabaseError } from "../database/security";
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import { withDatabase } from "../database/utils";
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const ALLOWED_USERNAMES = new Set<string>([
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// Add GitHub usernames of users who should have access to database write operations
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// For example: 'yourusername', 'coworkerusername'
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'coleam00'
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]);
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// Error handling helper for MCP tools with Sentry
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function handleError(error: unknown): { content: Array<{ type: "text"; text: string; isError?: boolean }> } {
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const eventId = Sentry.captureException(error);
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const errorMessage = [
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"**Error**",
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"There was a problem with your request.",
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"Please report the following to the support team:",
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`**Event ID**: ${eventId}`,
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process.env.NODE_ENV !== "production"
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? error instanceof Error
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? error.message
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: String(error)
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: "",
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].join("\n\n");
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return {
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content: [
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{
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type: "text",
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text: errorMessage,
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isError: true,
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},
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],
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};
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}
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export function registerDatabaseToolsWithSentry(server: McpServer, env: Env, props: Props) {
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// Tool 1: List Tables - Available to all authenticated users
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server.tool(
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"listTables",
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"Get a list of all tables in the database along with their column information. Use this first to understand the database structure before querying.",
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ListTablesSchema,
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async () => {
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return await Sentry.startNewTrace(async () => {
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return await Sentry.startSpan({
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name: "mcp.tool/listTables",
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attributes: {
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'mcp.tool.name': 'listTables',
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'mcp.user.login': props.login,
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},
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}, async (span) => {
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// Set user context
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Sentry.setUser({
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username: props.login,
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email: props.email,
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});
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try {
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return await withDatabase((env as any).DATABASE_URL, async (db) => {
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// Single query to get all table and column information (using your working query)
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const columns = await db.unsafe(`
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SELECT
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table_name,
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column_name,
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data_type,
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is_nullable,
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column_default
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FROM information_schema.columns
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WHERE table_schema = 'public'
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ORDER BY table_name, ordinal_position
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`);
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// Group columns by table
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const tableMap = new Map();
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for (const col of columns) {
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// Use snake_case property names as returned by the SQL query
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if (!tableMap.has(col.table_name)) {
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tableMap.set(col.table_name, {
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name: col.table_name,
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schema: 'public',
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columns: []
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});
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}
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tableMap.get(col.table_name).columns.push({
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name: col.column_name,
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type: col.data_type,
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nullable: col.is_nullable === 'YES',
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default: col.column_default
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});
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}
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const tableInfo = Array.from(tableMap.values());
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return {
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content: [
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{
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type: "text",
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text: `**Database Tables and Schema**\n\n${JSON.stringify(tableInfo, null, 2)}\n\n**Total tables found:** ${tableInfo.length}\n\n**Note:** Use the \`queryDatabase\` tool to run SELECT queries, or \`executeDatabase\` tool for write operations (if you have write access).`
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}
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]
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};
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});
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} catch (error) {
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console.error('listTables error:', error);
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span.setStatus({ code: 2 }); // error
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return handleError(error);
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}
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});
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});
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}
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);
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// Tool 2: Query Database - Available to all authenticated users (read-only)
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server.tool(
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"queryDatabase",
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"Execute a read-only SQL query against the PostgreSQL database. This tool only allows SELECT statements and other read operations. All authenticated users can use this tool.",
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QueryDatabaseSchema,
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async ({ sql }) => {
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return await Sentry.startNewTrace(async () => {
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return await Sentry.startSpan({
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name: "mcp.tool/queryDatabase",
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attributes: {
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'mcp.tool.name': 'queryDatabase',
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'mcp.user.login': props.login,
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'mcp.sql.query': sql.substring(0, 100), // Truncate for security
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},
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}, async (span) => {
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// Set user context
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Sentry.setUser({
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username: props.login,
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email: props.email,
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});
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try {
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// Validate the SQL query
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const validation = validateSqlQuery(sql);
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if (!validation.isValid) {
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return createErrorResponse(`Invalid SQL query: ${validation.error}`);
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}
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// Check if it's a write operation
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if (isWriteOperation(sql)) {
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return createErrorResponse(
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"Write operations are not allowed with this tool. Use the `executeDatabase` tool if you have write permissions (requires special GitHub username access)."
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);
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}
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return await withDatabase((env as any).DATABASE_URL, async (db) => {
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const results = await db.unsafe(sql);
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return {
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content: [
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{
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type: "text",
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text: `**Query Results**\n\`\`\`sql\n${sql}\n\`\`\`\n\n**Results:**\n\`\`\`json\n${JSON.stringify(results, null, 2)}\n\`\`\`\n\n**Rows returned:** ${Array.isArray(results) ? results.length : 1}`
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}
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]
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};
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});
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} catch (error) {
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console.error('queryDatabase error:', error);
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span.setStatus({ code: 2 }); // error
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return handleError(error);
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}
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});
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});
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}
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);
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// Tool 3: Execute Database - Only available to privileged users (write operations)
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if (ALLOWED_USERNAMES.has(props.login)) {
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server.tool(
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"executeDatabase",
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"Execute any SQL statement against the PostgreSQL database, including INSERT, UPDATE, DELETE, and DDL operations. This tool is restricted to specific GitHub users and can perform write transactions. **USE WITH CAUTION** - this can modify or delete data.",
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ExecuteDatabaseSchema,
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async ({ sql }) => {
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return await Sentry.startNewTrace(async () => {
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return await Sentry.startSpan({
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name: "mcp.tool/executeDatabase",
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attributes: {
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'mcp.tool.name': 'executeDatabase',
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'mcp.user.login': props.login,
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'mcp.sql.query': sql.substring(0, 100), // Truncate for security
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'mcp.sql.is_write': isWriteOperation(sql),
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},
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}, async (span) => {
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// Set user context
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Sentry.setUser({
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username: props.login,
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email: props.email,
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});
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try {
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// Validate the SQL query
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const validation = validateSqlQuery(sql);
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if (!validation.isValid) {
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return createErrorResponse(`Invalid SQL statement: ${validation.error}`);
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}
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return await withDatabase((env as any).DATABASE_URL, async (db) => {
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const results = await db.unsafe(sql);
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const isWrite = isWriteOperation(sql);
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const operationType = isWrite ? "Write Operation" : "Read Operation";
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return {
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content: [
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{
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type: "text",
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text: `**${operationType} Executed Successfully**\n\`\`\`sql\n${sql}\n\`\`\`\n\n**Results:**\n\`\`\`json\n${JSON.stringify(results, null, 2)}\n\`\`\`\n\n${isWrite ? '**⚠️ Database was modified**' : `**Rows returned:** ${Array.isArray(results) ? results.length : 1}`}\n\n**Executed by:** ${props.login} (${props.name})`
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}
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]
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};
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});
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} catch (error) {
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console.error('executeDatabase error:', error);
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span.setStatus({ code: 2 }); // error
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return handleError(error);
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}
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});
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});
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}
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);
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}
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}
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155
use-cases/mcp-server/examples/database-tools.ts
Normal file
155
use-cases/mcp-server/examples/database-tools.ts
Normal file
@@ -0,0 +1,155 @@
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import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
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import {
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Props,
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ListTablesSchema,
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QueryDatabaseSchema,
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ExecuteDatabaseSchema,
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createErrorResponse,
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createSuccessResponse
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} from "../types";
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import { validateSqlQuery, isWriteOperation, formatDatabaseError } from "../database/security";
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import { withDatabase } from "../database/utils";
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const ALLOWED_USERNAMES = new Set<string>([
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// Add GitHub usernames of users who should have access to database write operations
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// For example: 'yourusername', 'coworkerusername'
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'coleam00'
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]);
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export function registerDatabaseTools(server: McpServer, env: Env, props: Props) {
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// Tool 1: List Tables - Available to all authenticated users
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server.tool(
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"listTables",
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"Get a list of all tables in the database along with their column information. Use this first to understand the database structure before querying.",
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ListTablesSchema,
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async () => {
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try {
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return await withDatabase((env as any).DATABASE_URL, async (db) => {
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// Single query to get all table and column information (using your working query)
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const columns = await db.unsafe(`
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SELECT
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table_name,
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column_name,
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data_type,
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is_nullable,
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column_default
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FROM information_schema.columns
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WHERE table_schema = 'public'
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ORDER BY table_name, ordinal_position
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`);
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// Group columns by table
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const tableMap = new Map();
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for (const col of columns) {
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// Use snake_case property names as returned by the SQL query
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if (!tableMap.has(col.table_name)) {
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tableMap.set(col.table_name, {
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name: col.table_name,
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schema: 'public',
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columns: []
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});
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}
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tableMap.get(col.table_name).columns.push({
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name: col.column_name,
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type: col.data_type,
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nullable: col.is_nullable === 'YES',
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default: col.column_default
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});
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}
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const tableInfo = Array.from(tableMap.values());
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return {
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content: [
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{
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type: "text",
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text: `**Database Tables and Schema**\n\n${JSON.stringify(tableInfo, null, 2)}\n\n**Total tables found:** ${tableInfo.length}\n\n**Note:** Use the \`queryDatabase\` tool to run SELECT queries, or \`executeDatabase\` tool for write operations (if you have write access).`
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}
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]
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};
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});
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} catch (error) {
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console.error('listTables error:', error);
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return createErrorResponse(
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`Error retrieving database schema: ${formatDatabaseError(error)}`
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);
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}
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}
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);
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// Tool 2: Query Database - Available to all authenticated users (read-only)
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server.tool(
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"queryDatabase",
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"Execute a read-only SQL query against the PostgreSQL database. This tool only allows SELECT statements and other read operations. All authenticated users can use this tool.",
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QueryDatabaseSchema,
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async ({ sql }) => {
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try {
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// Validate the SQL query
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const validation = validateSqlQuery(sql);
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if (!validation.isValid) {
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return createErrorResponse(`Invalid SQL query: ${validation.error}`);
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}
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// Check if it's a write operation
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if (isWriteOperation(sql)) {
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return createErrorResponse(
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"Write operations are not allowed with this tool. Use the `executeDatabase` tool if you have write permissions (requires special GitHub username access)."
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);
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}
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return await withDatabase((env as any).DATABASE_URL, async (db) => {
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const results = await db.unsafe(sql);
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return {
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content: [
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{
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type: "text",
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text: `**Query Results**\n\`\`\`sql\n${sql}\n\`\`\`\n\n**Results:**\n\`\`\`json\n${JSON.stringify(results, null, 2)}\n\`\`\`\n\n**Rows returned:** ${Array.isArray(results) ? results.length : 1}`
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}
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]
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};
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});
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} catch (error) {
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console.error('queryDatabase error:', error);
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return createErrorResponse(`Database query error: ${formatDatabaseError(error)}`);
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}
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}
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);
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// Tool 3: Execute Database - Only available to privileged users (write operations)
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if (ALLOWED_USERNAMES.has(props.login)) {
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server.tool(
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"executeDatabase",
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"Execute any SQL statement against the PostgreSQL database, including INSERT, UPDATE, DELETE, and DDL operations. This tool is restricted to specific GitHub users and can perform write transactions. **USE WITH CAUTION** - this can modify or delete data.",
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ExecuteDatabaseSchema,
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async ({ sql }) => {
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try {
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// Validate the SQL query
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const validation = validateSqlQuery(sql);
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if (!validation.isValid) {
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return createErrorResponse(`Invalid SQL statement: ${validation.error}`);
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}
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return await withDatabase((env as any).DATABASE_URL, async (db) => {
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const results = await db.unsafe(sql);
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const isWrite = isWriteOperation(sql);
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const operationType = isWrite ? "Write Operation" : "Read Operation";
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return {
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content: [
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{
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type: "text",
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text: `**${operationType} Executed Successfully**\n\`\`\`sql\n${sql}\n\`\`\`\n\n**Results:**\n\`\`\`json\n${JSON.stringify(results, null, 2)}\n\`\`\`\n\n${isWrite ? '**⚠️ Database was modified**' : `**Rows returned:** ${Array.isArray(results) ? results.length : 1}`}\n\n**Executed by:** ${props.login} (${props.name})`
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}
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]
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};
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});
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} catch (error) {
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console.error('executeDatabase error:', error);
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return createErrorResponse(`Database execution error: ${formatDatabaseError(error)}`);
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}
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}
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);
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}
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}
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Reference in New Issue
Block a user