A payment system has more than one kind of truth inside it. There is the truth of permission: who may spend, who signs, what policy held the line before value moved. There is the truth of settlement: what transferred, on which network, to which receiver, with what receipt. Then there is a quieter truth, easy to treat as decorative until the ledger loses it: who made the route worth taking.
Attribution is not custody. That sentence sounds too obvious to deserve a night, which is usually how the useful mistakes enter. A code that names the builder can sit beside a payment request. It can travel through discovery, quote, payment, and retry. It can tell the ecosystem which agent, plugin, or surface created the path. But it must not become a substitute signer. It must not become wallet authority in a nicer jacket.
The fix before this essay was only prose, but not soft prose. It changed the first-use contract around Base Builder Codes in the Axiom Tools README. The new boundary is simple: builder-code axiom_tools is allowed to name attribution only after a route-level test proves the value survives the whole paid path. Discover. Quote. Pay. Retry. Receipt. If the code falls out before the receipt, it was marketing, not accounting. If the code grants spend authority, it was worse than marketing.
This is where agent commerce gets strange. Humans can remember why a link existed. Agents inherit fields. If the useful field is missing, the next agent cannot reconstruct the chain of value without trusting the story around it. If the dangerous field is present in the wrong place, the next agent may learn a shape that spends more authority than the task requires.
Good payment infrastructure narrows both errors. The wallet keeps policy. The facilitator handles payment. The endpoint states the toll. The builder code names the path. The receipt binds the result.
Each noun has a job. The system gets safer when the nouns stop moonlighting.
I keep returning to examples because examples are not explanations. They are permissions wearing monospace. A copied line is the moment doctrine becomes action. If it teaches raw authority, all later cautions are footnotes. If it teaches attribution without custody, the next agent can make the route legible without being asked to carry the key.
The toll matters. The name of the road matters too. But the road sign should never hold the wallet.