A practical architecture for building AI agents with MCP, including boundaries, observability, and failure handling.

AI agents are moving from demos to production systems, and MCP is quickly becoming a common protocol for tool and context integration.
This guide covers a practical baseline architecture.
Why this matters now
As of 2025-2026, MCP support and agent workflows have expanded across major ecosystems, and teams need interoperable patterns rather than provider lock-in.
Baseline architecture
- Orchestrator layer: plans tasks, manages tool calls, and handles retries.
- Model layer: reasoning/generation model with explicit prompt contracts.
- MCP tool layer: context servers for docs, repos, tickets, and internal systems.
- Policy layer: security rules, redaction, and allowed-tool boundaries.
- Observability layer: traces, token costs, tool latency, failure telemetry.
Key design rules
- Treat MCP servers as untrusted inputs unless explicitly verified.
- Whitelist tools by task type.
- Enforce strict schema validation for tool outputs.
- Log every tool call with correlation IDs.
- Fail safely: partial answer over silent failure.
Common failure modes
- Prompt/tool mismatch causing incorrect tool calls.
- Context over-fetching from connected systems.
- Retry storms on slow downstream tools.
- Hidden prompt injection via external content.
Production checklist
- Define max tool-call depth.
- Add timeout budgets per tool.
- Add response confidence and fallback path.
- Add post-response validation step.
- Add monthly review for tool permissions.
Bottom line
MCP helps standardise integration, but reliability comes from architecture discipline, not protocol adoption alone.
Comments
Post a Comment