[agent2agent] Re: New I-D : A Dimensional Model for Characterizing AI Agent Protocol Proposals and Their Substrates

[Sumit Ahuja <[e-mail]>]

Parisa, Iman, Blake,

One observation on D4;

Section 5.4 says a mediator can either preserve the originator's chain or terminate it and present its own credentials, and that the two have materially different audit and blast-radius implications. The model records the value per crossing. The consequence I would make explicit is what a downstream receiver can infer from it.

If a mediator terminates the chain at hop 2 and the next agent derives from the mediator, hop 3 is derived-chain. To the receiver at hop 3 it looks the same as a chain that runs unbroken back to the originator. The value at one crossing says nothing about whether an earlier crossing was local-policy.

It might be worth one sentence there saying that a derived-* value at a given crossing does not establish that the originator's authority survived every earlier crossing. It’s similar to the absence sentence Iman proposed: a local value, reported accurately, that a reader will otherwise take as more than it is.

Sumit P. Ahuja
Main Labs

On Thu, Oct 01, 2026 06:23 PM, Iman Schrock <team=[e-mail]> wrote:
> Hi Blake, Mikhail, Parisa,
> 
> Thanks for closing the loop, Blake. I’d keep your third rule as written, then put this sentence immediately after it:
> 
> “A record not found is reported as not found in the evidence set examined. That does not establish that the event did not occur. An absence conclusion needs a defined boundary and period, and grounds for believing every qualifying event would have left a record in that set.”
> 
> For the EXT-AUTHEV test: supply a third-party-verifiable EXT-AUDIT record and no EXT-AUTHEV record. The expected result is the audit record’s own verifiability and “not found in this evidence set” for authorization. Neither the audit value nor the missing record establishes whether authorization occurred.
> 
> Parisa, does that fit the section you’re preparing? I can turn it into a direct edit if useful.
> 
> Best,
> Iman
> 
> 
> 
> On Thu, 01 Oct 2026 09:32:56 +0000, Blake Morrison <[e-mail] <mailto:[e-mail]>> wrote:
> Hi Mikhail, Iman, Parisa,
> 
> Apologies for the delay.
> 
> Yes to adding it in the same section rather than as a fourth rule, and
> to Iman's "not found in this evidence set" as the expected result for
> the EXT-AUTHEV test. 
> 
> Nothing to add from me - Iman, it's yours to write up.
> 
> Blake
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