Metering and Settlement
Ajar lets owners price agent access and bind actions to settlement rails without becoming a payment system.
Agent traffic costs money. It can also create revenue. Ajar treats economics as part of the owner contract instead of leaving it as an afterthought.
The important boundary is this: Ajar declares pricing, metering, offers, and settlement adapters. It does not become the payment rail.
Before Ajar
Many sites see automated traffic as cost without attribution. Agents fetch heavy HTML, trigger search pages, hit APIs indirectly, and consume infrastructure. Owners can block, rate limit, or negotiate private deals, but they often cannot publish a simple machine-readable rule such as:
- public docs are free,
- commercial crawl reads cost this much,
- catalog search is free,
- purchase actions settle through this rail,
- simulate calls are free or separately metered,
- the signed offer is the authoritative price.
For actions, pricing can be even harder. A page may show one price, checkout may add tax and fees, inventory may change, and a payment provider may settle later. The agent needs to know which number is advisory and which number is binding.
What Ajar provides
Ajar's manifest can declare metering and accepted settlement adapters. A 402 response or action response can include an advisory price. For action execution, the signed Offer's total cost is authoritative.
That means the Kernel can compare the actual resolved cost against the mandate caps before commit. If the total cost exceeds the cap, the commit should not happen.
Ajar can work with settlement systems such as x402, AP2-card, MPP, or vendor adapters. The settlement proof references the Ajar receipt. The payment rail moves money; Ajar binds the payment-related action to mandate, offer, commit, and receipt.
Why this is useful
Owners get a way to state economics in the same place they state access policy. Agents get a way to discover cost before they act. Users and organizations get cap checks before money is spent.
This also helps separate read economics from action economics. A site might charge for high-volume reads, expose public docs for free, and only settle money when a purchase commit succeeds. Ajar can express those choices without forcing one business model.
What Ajar deliberately does not do
Ajar does not replace checkout, card networks, stablecoin payment protocols, bank rails, PSPs, or merchant systems. It composes with them.
That boundary keeps the protocol smaller. Ajar answers: was this action declared by the owner, authorized by the principal, accepted by the agent, and executed under signed terms? The settlement adapter answers: how did the money move?
The two records meet at the receipt.