FastMCP 3.0 is a framework for building smarter AI context apps, not just tool servers. Pull tools and data from anywhere, reshape them, control access, track state, and run long tasks — with hot reload, versioning, and observability built in for production use.
FastMCP 3.0is the platform MCP deserves in 2026, built to be as durable as it is future-proof:
We are moving beyond simple “tool servers.” We are entering the era of Context Applications—rich, adaptive systems that manage the information flow to agents.
The real challenge was never implementing the protocol. It’s delivering the right information at the right time. FastMCP 3 is built for that:
We've been adopters of FastMCP since the early days at Noodle Seed! - Super excited to see the launch of version 3.0!
@jlowin jlowin — “context applications” (state + ACL + long tasks + observability) is exactly where MCP gets painful at scale: multi-source fan-out + stale context + non-idempotent tool runs.
Best-practice: treat every tool call as a versioned contract (Pydantic schemas + semver), persist state as an event log (so you can replay/debug), and add distributed tracing with correlation IDs across sources/steps.
Q: is state storage pluggable (Redis/Postgres) with resumable long-jobs, and do you support per-user ACL down to field-level redaction in composed contexts? 🔥
love the shift to stateful context apps over just dumb tool servers. does this replace the need for LangGraph in simpler agents?
Can you tell a little bit more about what you do in version 3, please? How does it differ from 2?
Hey Chris, that line about the real challenge being delivering the right info at the right time, not implementing the protocol, is a good reframe. Was there a specific project where you had MCP working technically but the agent still wasn’t getting what it needed when it needed it?
Love the "context applications" framing - MCP isn’t hard, relevance is. Curious what you’ve seen as the biggest source of pain in practice: state across sessions, access control, or debugging/observability once you have multiple sources in the loop? Also - do you have an opinionated default for tracing tool calls end-to-end (so people don’t live in logs)?
Congrats on the launch — love how FastMCP is pushing MCP beyond “tool servers” into real context apps with state, access control, and observability built in.
From @jlowin :
FastMCP 3.0 is the platform MCP deserves in 2026, built to be as durable as it is future-proof: