Common Principles

What makes a specification a protocol

A layer designates a position in an architecture. A protocol specifies an exchange that can be implemented, executed and measured. That distinction imposes three requirements that an architectural specification does not. Each Cognition Protocol satisfies all three by construction rather than by observation.

Principle	What it requires
Convergence	The exchange provably reaches a fixed point, or terminates within a stated bound. Neither cycling nor unbounded deliberation is admissible, and a valid result exists at every step — the anytime property — so a deadline can truncate a run without invalidating what it has already produced
Benefit, certified rather than promised	The protocol emits a machine-readable artifact recording what was achieved and, where the objective was not met, the precise shortfall
Cost, bounded a priori	An exact ceiling on rounds, candidate outcomes, agent evaluations and model calls — reported when the run opens, reconciled against actual spend when it closes

Portability

A protocol is portable only if it is specified independently of the transport it runs over. Each Cognition Protocol is a self-contained definition together with one transport binding per L8 transport it supports.

Concern	For A2A
Field mapping	Protocol URI in message.extensions, phase and role in message.metadata, content in message.parts
Discovery	The agent card's extension list and the skill's declared media types
Session correlation	The existing contextId

Where all agents are under common control, uniform support can be asserted by construction and discovery omitted. Discovery becomes mandatory once third-party agents participate.

Scope boundary

Cognition Protocols maintain shared state within a coordination session only. The following are out of scope:

• Governance and policy enforcement — owned by the Cognition Engines area.
• Persistent memory and knowledge graphs — owned by the Cognition Fabric.