Tool-Router Gateway Pattern
Conceptual Architecture: Type-safe tool discovery, routing, and circuit-breaking proxy for LLM agents
Context & Core Problem
Providing an agent with 50+ tool definitions degrades tool-calling accuracy, increases input token overhead, and introduces dangerous tool hallucination risks.
Architectural Approach & Decisions
Designed a two-tier semantic tool retrieval layer that exposes only top-k relevant tool schemas per turn, wrapped in an active circuit breaker with strict rate-limiting and fallback definitions.
Verifiable Evidence & Observable Outcomes
Design Specification: Top-k schema filtering and active circuit breaker prevent tool hallucination and isolate cascading failure modes.
Empirical Result
Specification for type-safe tool discovery and circuit breaker failover compatible with the Model Context Protocol (MCP).
System Architecture & Data Flow
Agent Action Request
Intercepts candidate tool name and raw argument object
Schema Matching
Validates against strict versioned schema repository
Circuit Check
Verifies upstream tool endpoint health and quota headroom
Clean Dispatch
Executes in isolated sandbox with timeout and telemetry
Technical Architecture Specifications
Transparent Limitations & Governance Boundaries
Conceptual reference architecture illustrating gateway design; not a commissioned client engagement.