Re: draft-helixar-hdp-agentic-delegation-01: chain-of-custody for agentic delegation (revision, seeking review)

Hi Siri, all,
We read -01 closely — two comments on the open questions, then a pointer to a complementary design we would like review on.
On question 1 (hop signing keys): this seems to depend on what the token is for. For an offline-verifiable evidence trail, the single-key default is coherent. For runtime authorization it seems insufficient: with one issuer key, a hop attests that the issuer recorded a delegation, not that the delegating agent cryptographically consented to it. We took the other branch of your trade-off — per-hop signatures by each delegator's own key — and accepted losing offline verification.
On question 2 (truncation): from the capability side, if the verifier requires the chain to terminate exactly at the authenticated presenter — as UCAN Invocation ("ending at the invoker") and ZCAP's capabilityInvocation proof already require — deleting trailing hops gains an attacker nothing: authority only narrows toward the tail, so a truncated prefix is only usable by the delegatee of its last remaining hop, who legitimately holds that authority anyway. A signed chain-length commitment may therefore be unnecessary for authorization; completeness stays an audit question, where your out-of-band suggestion looks right.
We have published a design (design only, no implementation yet) that is roughly the capability-layer complement to HDP's provenance layer: per-hop independent signatures, MUST-level monotonic attenuation (capabilities ⊆ parent, caveats grow-only, expiry shrink-only, unknown caveat rejects the chain), chains rooted in a KYB-verified entity's attested behavior boundary, and revocation via 60-second-TTL status credentials — bounded mid-chain revocation, cf. your §10.6. Deviations from UCAN/ZCAP are declared per clause:
https://github.com/jiaozi-protocol/jiaozi-app/blob/main/standards/delegation-v1/DESIGN.md <https://github.com/jiaozi-protocol/jiaozi-app/blob/main/standards/delegation-v1/DESIGN.md >
Feedback is very welcome, including "use X instead".
Thanks, 
Brigitte Qirong LI 
Jiaozi Protocol
https://www.jiaozi.io <https://www.jiaozi.io >