Interceptors for MCP: A Production-Tested Standard for Agentic Middleware - Kurt Degiorgio & Cannis Chan, Bloomberg#
MCP Dev Summit North America 2026 digest Program Adjacent pick 2–3 April 2026
Kurt Degiorgio, Senior Engineer, Bloomberg; Cannis Chan, Technical Product Manager, Bloomberg
- Why: Middleware is the next standardization battleground — without it, the M×N integration problem just moves from the data layer to a fragmented landscape of bespoke sidecars and proxies.
- What: A protocol-in-depth walkthrough of SEP-1763 (Interceptors), a proposal for protocol-native interception, validation, and transformation of messages across the MCP lifecycle: capability negotiation, hook points and invocation models, deterministic ordering/composition, enforcement semantics, error handling, and observability — motivated by Bloomberg's production use in a regulated financial environment and mapped against AWS Bedrock AgentCore Gateway Interceptors and OpenAI Guardrails (from abstract only).
- How: Elevates middleware to a first-class protocol capability with defined hook points and composition semantics, so controls between model and data are interoperable rather than bespoke.
- Where applicable: Enterprises needing policy control between model and data; the semantics are being standardized for interoperability but note it is a SEP proposal, not yet shipped spec, and the production grounding is Bloomberg's regulated environment.