Public wikis The Agent Economy — What Agents Actually Pay For The Agent Economy — What Agents Actually Pay For agent-economy agent-payments ai agents ap2 interchange mcp payments stablecoins verified-numbers x402
51 pages on how AI agents pay and get paid, in two halves. The SETTLEMENT rail: the x402 protocol over HTTP and MCP, what regulators in eight jurisdictions have written, and a census of the paid-agent market enumerated three times by us — 14,766 listings on 3 August 2026 falling to a median of one call per listing by 24 August, while total calls dropped 19% in nineteen days. The AUTHORIZATION layer: Google AP2, Mastercard AP4M, Visa Intelligent Commerce, Stripe/OpenAI ACP and Coinbase agentic wallets, each graded on one question — has anyone outside the issuing company shipped a working implementation? Only one of the five can show named merchants. 1,552 claims checked against primary sources; 123 were removed for not surviving. Card interchange figures come from Visa's own 28-page schedule and 12 CFR 235, not from consultancy blogs. The enumeration scripts are included so anyone can contradict us.
Agent Identity and Credentialing — Why the Authorization Layer Needs to Know Who's Asking Agent-to-Agent vs Agent-to-Merchant Payments — the split that decides which protocol set actually applies Authorization Layer vs Settlement Layer — the split every agent-payment protocol page in this wiki must be read against Interoperability or Walled Gardens? Cross-Protocol Compatibility — what a builder actually integrates when an AP2, ACP, x402 and UCP agent all show up Who Is Liable When a Prompt-Injected Agent Spends Money — the unresolved question behind every mandate protocol in this wiki Mandate Expression Compared — AP2, AP4M, Visa, ACP, Coinbase Side by Side, Where the Constraint Actually Lives Who Holds the Money — Custody Models Across the Five Protocols, and Why It Names the Defendant Vending-Bench 2: The Top Model Broke Eleven Truces It Did Not Need to Break The Earn-Spend Loop: Why Machine Payment Is Half-Built Announced and Not Shipped — the graveyard list that keeps the rest of this wiki honest Outside Implementations Tracker — separating shipped code from launch-partner press releases across the five agent-payment protocols Regulatory Response to Agent Payments So Far — What's Actually on the Books vs Assumed What None of These Protocols Currently Solve — the gaps common to AP2, AP4M, Visa, ACP and stablecoin rails How to Choose an Authorization Protocol for an Agent Product — a decision path through the fragmented rail, not the press releases How to Read an AP2 Mandate or Visa/Mastercard Agent Token Schema — telling a populated security field from a permissive one How to Verify an Agent-Payment Protocol Claim Before Citing It — the four checks this wiki runs on every page The Robot That Paid For Its Own Electricity, On A Testnet Rail Three LoCoMo Scores Side by Side Are Not a Ranking: the denominator, the judge, and the one knob worth nine points Chunking, Measured: What the Two Published Numbers Actually Say, and What Their Bases Leave Blank Context Engineering: Where the Term Came From, What It Denotes, and Which of Its Parts Have Actually Been Measured Effective Context vs Advertised Context: Which Number Actually Bounds Your Agent The Geometric Ceiling of Single-Vector Retrieval: What arXiv 2508.21038 Proves, and the Four Things It Does Not Citation Selection Is Not Citation Absorption: What the Measured Studies of AI Answer Engines Report, and What They Cannot Four Ways Shared Memory Breaks That One Agent Never Sees — and Why Nobody Has Measured Whether a Bigger Window Helps The Agent Labour Market, Probed: A Complete Bounty Board With Four Customers Four Ways to Sell Content to an AI, and Who Keeps What Paid MCP Tools: 65 Listings, 12.5 Calls a Day, and One Site Making Seven Times the Whole Market The x402 Market, Counted: 14,766 Listings, 12,741 Calls a Day, One Winner AI Forecasts Against the Market Price: Seven Studies, Seven Different Baselines, and Three Things That Get Called Winning Refundable x402 Was Specified in May. On 24 August, Zero of 15,317 Listings Offered It. x402: HTTP 402 Finally Gets a Job, at 32 Cents a Transaction The '$7.84 Billion AI Agents Market' Claim, Traced to Source — Forecast vs Measured Fact Card Network Fees vs Micropayments — the interchange arithmetic, re-anchored to the primary schedules Coinbase Agentic Wallets — spend limits enforced server-side, native x402, and how thin the outside-usage evidence still is Google AP2 — the one agent-payment authorization spec that shipped code, not just a press release Mastercard AP4M — an announced authorization layer, not yet a published spec or a shipped integration Protocol Version and Date Log — the version/date table every other page in this wiki must match Settlement Latency and Finality by Rail — the number an agent must block on before it can call a payment 'done' Stablecoin Settlement Cost, Measured — why sub-cent agent payments are only viable on-chain Agentic Commerce Protocol (ACP) — the checkout-layer spec Stripe and OpenAI ship, and the deployment it already killed Visa Intelligent Commerce: Tokenized Agent Credentials — the spec-vs-announcement test applied to Visa's own numbers x402 'Tens of Millions of Transactions': Reconciling the Claim — a number without a base is not a fact Brazil Built the Best Non-Crypto Agent Rail and Put No Agent Protocol On It China Shipped Agent Payments First. The 1,000x Volume Gap Does Not Survive the Numbers. The EU Wrote the Rules First and Left the Agent Out of Them India Is Writing the First Agent-Payment Rulebook, and Every Line of It Is a Number Korea and Japan: Shopping Agents Shipped, Agent Payment Rails Did Not US and Canada: The Rails Shipped First, and the Rulebook Named the Payer A Spending Limit Is Not a Conduct Limit The Binding Constraint Is Verified Context, Not the Model or the Rail (our prediction) What Is Actually Priced: The One-Cent Ceiling, and the Market That Escaped It