{"what":"The Base EIP-3009 Settlement Tape — a verifiable FLOOR on gasless x402-style USDC settlement on Base. Not total x402 volume.","status":"measuring","note":"citable day = 2026-09-12 (frozen at UTC midnight). today_so_far is provisional and NOT citable.","latest_full_day":{"day":"2026-09-12","status":"measuring","mature":false,"tail_note":"indexing stopped before the day ended — tail unrecorded, day not citable","rail_tx_count":194,"rail_volume_usd":1374.65,"rail_wash_suspect_n":6,"rail_wash_suspect_volume_usd":0.31,"rail_pct_wash_by_count":3.1,"rail_pct_wash_by_value":0,"clean_volume_usd":1374.34,"value_share_ge_1usd_pct":99.6,"median_payment_usd":0.021984,"coverage_pct":1},"today_so_far":{"day":"2026-09-14","as_of_ts":null,"rail_tx_count":0,"rail_volume_usd":0,"rail_wash_suspect_n":0,"rail_wash_suspect_volume_usd":0,"rail_pct_wash_by_count":0,"rail_pct_wash_by_value":0,"clean_volume_usd":0,"value_share_ge_1usd_pct":0,"median_payment_usd":0,"coverage_pct":0,"blocks_indexed":0,"blocks_skipped":24968,"ranges_skipped":["51277061-51277300","51277301-51277539","51277540-51277781","51277782-51278022","51278023-51278263","51278264-51278504","51278505-51278740","51278741-51278979","51278980-51279221","51279222-51279459","51279460-51279700","51279701-51279943","51279944-51280178","51280179-51280422","51280423-51280659","51280660-51280899","51280900-51281144","51281145-51281379","51281380-51281620","51281621-51281859","51281860-51282102","51282103-51282344","51282345-51282580","51282581-51282819","51282820-51283058","51283059-51283299","51283300-51283541","51283542-51283779","51283780-51284018","51284019-51284264","51284265-51284499","51284500-51284740","51284741-51284979","51284980-51285220","51285221-51285460","51285461-51285698","51285699-51285940","51285941-51286180","51286181-51286422","51286423-51286658","51286659-51286899","51286900-51287145","51287146-51287380","51287381-51287620","51287621-51287860","51287861-51288102","51288103-51288350","51288351-51288580","51288581-51288821","51288822-51289060","51289061-51289301","51289302-51289545","51289546-51289784","51289785-51290021","51290022-51290259","51290260-51290498","51290499-51290753","51290754-51290978","51290979-51291220","51291221-51291463","51291464-51291709","51291710-51291941","51291942-51292178","51292179-51292420","51292421-51292662","51292663-51292901","51292902-51293143","51293144-51293382","51293383-51293622","51293623-51293865","51293866-51294106","51294107-51294348","51294349-51294581","51294582-51294819","51294820-51295066","51295067-51295301","51295302-51295546","51295547-51295787","51295788-51296023","51296024-51296261","51296262-51296507","51296508-51296744","51296745-51296986","51296987-51297218","51297219-51297458","51297459-51297705","51297706-51297955","51297956-51298183","51298184-51298421","51298422-51298661","51298662-51298913","51298914-51299148","51299149-51299378","51299379-51299619","51299620-51299862","51299863-51300100","51300101-51300345","51300346-51300586","51300587-51300824","51300825-51301067","51301068-51301298","51301299-51301539","51301540-51301779","51301780-51302028"],"status":"measuring","provisional":true},"scope":{"chain":"base","asset":"USDC (native, 0x833589...2913)","scheme":"EIP-3009 transferWithAuthorization / receiveWithAuthorization (AuthorizationUsed, authorizer == sender)","framing":"FLOOR — a verifiable lower bound on gasless x402-style USDC settlement on Base. NOT total x402 volume."},"out_of_scope":["Permit2 / 'upto' / deferred x402 schemes (no AuthorizationUsed event)","facilitator-batched settlements that don't emit per-payment authorizations","x402 on other chains (Injective, Solana, ...) and non-USDC assets","linked-wallet, multi-hop (A->B->C->A) and multi-day self-dealing — invisible to the round-trip fingerprint and NOT claimed","history before 2026-07-02 (tape start; near-head RPC cannot backfill)"],"method":"rail settlement = USDC Transfer whose tx has AuthorizationUsed with authorizer == sender; wash-suspect = self-loop OR exact round-trip (reverse transfer within ±20% amount, ±1h), flagged at detection time and kept even after the reverse leg leaves the 72h window. Conservative under-count by design. Headline % is by COUNT; value view is outlier-dominated. median_payment_usd is estimated by log-bucket interpolation, not an exact order statistic.","methodology_version":"1.0.0","methodology_url":"https://agentflow.watch/rail#methodology","license":"CC-BY-4.0 — cite as: AgentFlow Base Settlement Tape v1.0.0, <UTC date>","receipts":"https://agentflow.watch/rail/receipts.json","history":"https://agentflow.watch/history.json (rail_* fields, daily)"}