MCP in one paragraph
MCP — Model Context Protocol — is the standard Anthropic published in late 2024 for letting Claude (and other AI models that support it) invoke tools and read resources from external systems. An MCP server is the bridge: your CRM, your database, your internal API can be wrapped in an MCP server, and Claude clients (Claude Desktop, Claude Code, agent applications) can then call into them. MCP is the production engineering surface that turns Claude from a chat interface into an operational system.
What MCP enables
MCP is the mechanism that lets Claude take actions outside its own context. Without MCP, Claude can read text and produce text. With MCP, Claude can:
- Query your CRM for customer history
- Read documents from your knowledge base
- Look up rows in your database
- Trigger workflows in your business systems
- Update records under defined permission scopes
- Compose multi-step workflows that span tools
The abstraction matters because it standardises how Claude talks to external systems. Before MCP, every integration was bespoke; with MCP, your custom servers plug into any MCP-compatible client.
MCP server architecture
A production MCP server has more responsibility than a demo MCP server:
- Authentication: Per-tenant credentials, scope-restricted tool access, no implicit trust of the Claude client side
- Tenancy: Multi-tenant data filtering, tenant context propagation across tool calls, audit logs separable per tenant
- Audit logging: Every tool invocation logged with caller identity, parameters, response, latency, outcome — exportable to SIEM
- Rate limiting: Per-tenant and per-tool rate limits, queue-based fairness, back-pressure surfaced to the client
- Schema evolution: Versioned tool definitions, deprecation windows, consumer-driven contracts to catch breaking changes in CI
- Operational runbooks: Incident-response playbooks, on-call rotation, observability dashboards
Most first-version MCP servers ship without these. Production MCP servers must include them.
When to build a custom MCP server
Off-the-shelf MCP servers exist for common SaaS platforms (Slack, GitHub, Linear, etc.). You need a custom MCP server when Claude needs to talk to your internal systems — your proprietary database, your in-house API, your data warehouse, your billing platform. NINtec's MCP server engineering practice ships custom servers for exactly this — auth, tenancy, audit, evolution, and on-call coverage built in from architecture phase.