Tools
fastmcp cut three patches in ten minutes to route progress and streamed content through a request-scoped notifier
On 2026-09-07 punkpeye/fastmcp published v4.20.4 at 22:55Z (tool progress through the request-scoped notifier, #362), v4.20.5 at 23:02Z (settle failing custom route streams, #360), and v4.20.6 at 23:05Z (streamContent through the same notifier). The pattern is one bug found twice: progress and streamContent were both escaping the per-request notification scope, which in a concurrent server means notifications landing on the wrong request. Anyone on 4.20.3 or earlier running concurrent tool calls should go straight to 4.20.6.
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