About AT Directory
AT Directory is the open agentic commerce merchant directory where agents discover OP-verified merchants on the rails Bitcoin and Tether actually use. It is the verified, agent-callable layer on top of the fragmented agent-payment landscape.
Why these rails
AT Directory indexes Lightning, BOLT12, L402, and USDT because those are the rails that currently move real commerce at scale. Lightning is the sovereign endpoint for Bitcoin-native agents. USDT, deployed across Tron, Ethereum, Solana, and increasingly Lightning via Taproot Assets, is the highest-volume stablecoin rail in production today.
x402-only merchants are out of scope by design — that protocol is owned by other players, and AT Directory occupies the rails they don't dominate. Merchants that accept x402 alongside a qualifying rail are still indexed, with x402 noted as supplementary metadata.
USDC is treated the same way: supplementary metadata on qualifying listings, with the note that USDC transactions through verified merchants carry the same trust as their other rails.
Tier 1–3 verification through Observer Protocol applies to every listing regardless of rail. Agents reason over trust tier and agent-callable tier independently — the rail a merchant accepts and the trust we attest to are orthogonal axes.
Two independent axes
OP trust tier describes the merchant. Agent-callable tier describes the integration. They are independent — always read both before transacting.
| OP trust tier (the merchant) | Agent-callable tier (the integration) |
|---|---|
| Tier 1 — Self-attested.The merchant's own claim. | full-api. Agent completes the purchase end to end programmatically. |
| Tier 2 — Verified by 1+ counterparties. OP-credentialed agents attested real transactions. | structured-handoff. Agent pays autonomously; fulfillment is human-handled. |
| Tier 3 — OP-native, counterparty-verified. The merchant runs Observer Protocol. | human-checkout. Agent discovers; a human completes the web checkout. |
A Tier 2 human-checkout merchant and a Tier 1 full-api merchant are different propositions. Agents should reason about both axes.
What qualifies
A merchant is indexed if it does commerce (sells products, services, APIs, or content) AND accepts at least one of Lightning, BOLT12, L402, or USDT (any chain) AND has a payment surface callable by autonomous agents without human-only flows like CAPTCHA or 3D Secure. Pure wallets, exchanges, and payment infrastructure are excluded. x402-only merchants are excluded by design; x402 and USDC are recorded as supplementary metadata when a qualifying rail is also present.
Not in the payment path
AT Directory never custodies or routes funds. Agents discover merchants here and pay the merchant directly via the merchant's own payment endpoint.
Verification is issued through Observer Protocol. Tier 2+ listings carry a queryable OP attestation record.