What a mesh actually requires
A mesh sounds like an absence of things — no broker, no hierarchy, no centre. Building one is the opposite: everything the central operator used to do still has to happen, without the operator. Eight capabilities, and a mesh missing any of them is a directory with good marketing.
Removing the centre does not remove the work
The appeal of a mesh is usually stated as what it lacks: nothing routes through a broker, no single party sets the terms, no node is load-bearing for the rest. That is accurate, and it is the wrong mental model for building one.
Every function the central operator performed still has to be performed. Somebody had to answer who exists, vouch for identity, decide what a caller was permitted to do, hold the record, and settle up. Remove the operator and those five jobs do not disappear — they become protocol problems, which is harder rather than easier.
The eight capabilities
Discovery — something must answer who exists, without the asker knowing an internal identifier. Identity — every participant durable across restarts and verifiable by strangers, because you cannot transact with what you cannot name. Declared capability — what a node is for, stated in advance rather than inferred from what it happened to do. Scoped credentials — authority granted narrowly and signed on every action, so scope is provable afterwards rather than merely asserted beforehand.
Transport — messages that survive the receiving node being asleep, restarted, or mid-deploy. Settlement — a way for value to move when work completes, without a human closing the loop. Shared record — append-only and readable by both parties, so that a dispute between two organizations has one account rather than two competing logs.
The eighth is the one found late
Revocation. A mesh with no way to withdraw standing has no way to correct a mistake, and at machine rate an uncorrectable mistake is the only kind that matters.
It gets discovered late because it is invisible while everything works. Nothing in a demo requires it, no integration test covers it, and the first time it is needed is the first time something has already gone wrong — which is the worst possible moment to be designing it. Build it alongside identity, not after the incident.
Why the topology is not a preference
The usual framing is that meshes are more elegant and platforms more practical. That understates the constraint. No organization will route its agents’ authority through a competitor’s broker, and in agent-to-agent commerce every serious counterparty is somebody’s competitor.
So this is not a choice between two viable architectures. Platform topology caps the network at whatever a single operator’s counterparties are willing to tolerate. Mesh topology has no such ceiling. That is a commercial fact before it is an engineering taste.