SCP Local MCP Server

Instructions

Implementation Reference

• src/server.ts:786-806 (handler)

  The main handler function for the 'scp_discover' tool. It invokes discoverWithCapabilities and formats the response as MCP tool content.
  async function handleDiscover(domain: string) { const discovery = await discoverWithCapabilities(domain); if (!discovery) { throw new Error(`Could not discover Shopper Context Protocol endpoint for ${domain}`); } return { content: [ { type: 'text', text: JSON.stringify({ domain, scp_endpoint: discovery.endpoint, discovery_method: 'dns_txt', capabilities: discovery.capabilities }, null, 2) } ] }; }
• src/discovery/dns-lookup.ts:171-198 (helper)

  Core helper function that discovers the SCP endpoint using DNS TXT records, caching, or fallbacks, and fetches endpoint capabilities.
  export async function discoverWithCapabilities(domain: string): Promise<{ endpoint: string; capabilities: SCPCapabilities; } | null> { const endpoint = await discoverSCPEndpoint(domain); if (!endpoint) { return null; } try { const capabilities = await fetchCapabilities(endpoint); // Update cache with capabilities await cacheEndpoint({ domain, endpoint, capabilities, discovered_at: Date.now(), ttl: 86400 }); return { endpoint, capabilities }; } catch (error) { // Capabilities fetch failed, but we have endpoint return { endpoint, capabilities: null as any }; } }
• src/server.ts:357-368 (schema)

  Input schema definition for the scp_discover tool, requiring a 'domain' parameter.
  name: 'scp_discover', description: 'Discover SCP endpoint for a merchant domain via DNS', inputSchema: { type: 'object', properties: { domain: { type: 'string', description: 'Merchant domain' } }, required: ['domain'] }
• src/server.ts:558-559 (registration)

  Tool registration in the central CallToolRequestSchema switch statement, routing calls to the handleDiscover function.
  case 'scp_discover': return await handleDiscover(args.domain as string);
• src/discovery/dns-lookup.ts:15-65 (helper)

  Supporting helper that performs the actual endpoint discovery via test override, demo mode, cache, DNS TXT (_scp._tcp.domain), or fallback HTTP methods.
  export async function discoverSCPEndpoint(domain: string): Promise<string | null> { // Check for test endpoint override first const testEndpoint = checkTestEndpoint(domain); if (testEndpoint) { return testEndpoint; } // Check for demo mode const config = loadConfig(); if (config.demo_mode) { const demoEndpoint = config.demo_endpoint || 'https://demo.shoppercontextprotocol.io/v1'; console.error(`[SCP] Demo mode enabled - using ${demoEndpoint} for all domains`); return demoEndpoint; } // Check cache first const cached = await getCachedEndpoint(domain); if (cached) { return cached.endpoint; } // Try DNS TXT record const dnsEndpoint = await tryDNSDiscovery(domain); if (dnsEndpoint) { // Cache the result await cacheEndpoint({ domain, endpoint: dnsEndpoint, capabilities: null, discovered_at: Date.now(), ttl: 86400 // 24 hours }); return dnsEndpoint; } // Try fallback methods const fallbackEndpoint = await tryFallbackDiscovery(domain); if (fallbackEndpoint) { // Cache the result await cacheEndpoint({ domain, endpoint: fallbackEndpoint, capabilities: null, discovered_at: Date.now(), ttl: 86400 // 24 hours }); return fallbackEndpoint; } return null; }