01 / The operating case
What changes in a real workflow?
A client brings an analytics-server token to a payroll MCP server.
- 01Authority origin
- 02Task and grant
- 03Current decision
- 04Observed outcome
02 / Decision contract
What the executor must check
Verify token issuer, signature or introspection, expiration, canonical resource audience and required scope before any tool call.
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
Issuer-valid tokens for another server are accepted.
Evidence to retain
Record issuer and audience validation result, request ID and denial, without token contents.
04 / Canonical scope
Why this reference stands alone
Resource indicators describes client token acquisition; this guide owns the receiving-server negative test.
Illustrative implementation artifact
Audience negative tests
token for server A -> server A: accept only after all checks
token for server A -> server B: reject audience mismatch
expired token for server A -> server A: reject expiry
valid token + insufficient tool scope -> reject tool callPrimary references