FastMCP Cloud

FastMCP Cloud now presents itself as Prefect Horizon, a managed gateway and governance layer for operating FastMCP and other Model Context Protocol servers in production.

Verified capabilities and evidence

The fetched homepage says Build it with FastMCP and Run it on Horizon, describing the product as an MCP gateway and governance layer for enterprise agents. It offers a secure way to manage and control servers in production, a free starting option, more than 82 million FastMCP downloads per month, and a claim that FastMCP powers 70% of MCP servers worldwide. Those adoption figures are vendor claims and may reflect package downloads rather than distinct production servers. The old FastMCP Cloud pricing URL redirected to a Horizon sign-in page, so no stable amount was available.

Workflow and differentiation

A developer defines tools and resources with FastMCP, then uses Horizon as the controlled entry point for agents. A gateway should centralize authentication, routing, policy, and visibility instead of exposing each server independently. That is valuable when multiple agent teams share internal systems: administrators need to know which identity called which tool, what arguments were passed, whether it succeeded, and which policy allowed it. A gateway does not remove authorization inside the underlying API or database. Tool descriptions, argument schemas, timeouts, retries, and destructive-action approvals still require deliberate design.

Pricing and total cost

The homepage offers Get started for Free, but the pricing route displayed only sign-in controls. No monthly price, seat count, request quota, server limit, log retention, enterprise minimum, or overage schedule was verifiable. Treat free access as an invitation to test, not evidence of unlimited production use. Request a dated quote covering requests, active servers, organizations, environments, identities, audit retention, SSO, support, and egress. Compare total cost with self-hosting FastMCP plus identity, a reverse proxy, log storage, upgrades, backups, and on-call ownership. Each alternative has costs beyond compute.

Pros, cons, and evidence gaps

Horizon fits naturally with FastMCP and comes from the team behind FastMCP and Prefect, potentially reducing framework-to-hosting friction. Central governance can be safer than distributing credentials to many agents. The biggest limitations are pricing opacity and unclear public detail about policy language, supported transports, regional hosting, private networking, availability, disaster recovery, and exportable audit logs. Enterprise buyers should verify each item rather than infer it from secure branding. They should also test whether policy decisions remain understandable during incidents and whether logs expose or redact sensitive arguments.

Practical evaluation plan

Deploy a read-only documentation server, a staging ticket writer, and a denied sensitive action. Test identity, per-tool authorization, secret isolation, revocation, concurrency, timeout handling, schema changes, logs, alerts, and failure behavior. Attempt prompt-injection and confused-deputy scenarios before granting writes. Compare AgentHost and AI Agent Host. Use the MCP explanation, production deployment guide, and agent observability guide to define acceptance criteria.