# `ExMCP.Server.CancellationTracker.Default`
[🔗](https://github.com/azmaveth/ex_mcp/blob/v1.0.0/lib/ex_mcp/server/cancellation_tracker.ex#L30)

Default cancellation tracker.

Supports the two conventions ExMCP handlers use to observe cancellation:

* a `:cancelled_requests` `MapSet` in the handler state, which is updated
  in place, and
* an `:active_requests` map of `request_id => pid`, whose worker process is
  sent `{:cancelled, request_id}` so long-running work can stop early.

Handler states that use neither are returned untouched.

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*Consult [api-reference.md](api-reference.md) for complete listing*