Middleware state not persisting to tool handlers

8/10 High

Middleware state set during request processing was not correctly being propagated to tool handler functions, breaking authentication and request context flows in production.

FastMCP
Category
architecture
Workaround
none
Stage
deploy
Freshness
declining
Scope
single_lib
Upstream
open
Recurring
No
Buyer Type
team
Maintainer
active

Sources

Collection History

Query: “What are the most common pain points with FastMCP for developers in 2025?”4/8/2026

Middleware state that wasn't surviving the trip to tool handlers now does

Created: 4/8/2026Updated: 4/8/2026