MCP long-running task security

A durable task can outlive the authorization context in which it began.

01 / The operating case

What changes in a real workflow?

A report-export task is queued while permitted, then its requester loses access before the export worker starts.

Trace the authority boundary
  1. 01Client / task
  2. 02MCP server
  3. 03Tool call + arguments
  4. 04Downstream effect

02 / Decision contract

What the executor must check

Persist the originating principal, task and target, recheck current authority before effect, and bind retrieval of task results to the same resource and tenant.

InputPrincipal · task · action · target
DecisionGrant ancestry · policy · current state
ResultEnforce · record · verify outcome

03 / Failure and evidence

What goes wrong, and what can be proven?

Failure mode

A valid task identifier is treated as a bearer grant to resume or retrieve another user’s result.

Evidence to retain

Record task creation, state changes, reauthorization, effect and result access.

04 / Canonical scope

Why this reference stands alone

MCP revocation treats withdrawn grants generally; this page owns queued execution and result retrieval.

Protocol or attack trace

Deferred task state

Sequence

Export task is queued under grant G; G expires before worker start; another user obtains task ID.

Negative test

Worker denies expired grant and result retrieval denies a principal outside task ownership.

Primary references

Read the underlying material

Architecture discussion

Choose one consequential action and make its boundary explicit.

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