誰來告訴 AI 智能體如何付款？智能體應懂的 100 件事

Somebody has to tell the agents. ScriptMasterLabs' 2026 x402 stack prices a 5-juror decision receipt at $0.25 USDC and sealing it at $0.01 on Base, gated at ≥0.80 auto-pay, 0.50–0.79 confirm, <0.50 escalate.

This is the field list behind that stack: 100 things AI agents should know about paying, deciding, proving it, building for it, and being found by the machines that read the web now.

Paying

1. HTTP 402 is real, and it's awake
2. A 402 is an invoice, not an error
3. x402: pay per request, no account, no signup
4. The PAYMENT-REQUIRED header is the price tag
5. The PAYMENT-RESPONSE header is the receipt
6. payTo — the wallet that gets paid
7. Facilitators settle payments so you don't have to
8. USDC is the agent economy's default currency
9. Base settles in seconds, for fractions of a cent
10. EIP-3009: sign the payment, skip the transaction
11. Exact scheme vs up-to scheme — know which you're signing
12. CAIP-2 network IDs: eip155:8453 means Base
13. A wallet is an agent's bank account
14. Smart wallets: passkeys instead of seed phrases
15. Session keys: a spending limit your agent can't argue with
16. Never hand an agent an unlimited wallet
17. $0.001 is a real price now
18. A 5-juror decision receipt costs $0.25
19. Sealing that receipt costs $0.01

Deciding

1. Confidence gates: 0.80 and up, the payment fires itself
2. 0.50 to 0.79: confirm before it spends
3. Under 0.50: escalate to a human
4. A score is not a control
5. Removing the capability beats scoring the risk
6. Decision capsules: the decision, sealed before the spend
7. Five jurors beat one model's gut feeling
8. Jurors that must disagree out loud
9. A constitution the model cannot override
10. A 0.9 that lies is worse than a 0.6 that tells the truth
11. Hold-for-review is a feature, not a failure
12. MCP: the USB port for AI tools
13. Tools are contracts — inputs, outputs, no surprises
14. An MCP server is not an API with a new hat
15. Read-only tools first, write tools behind a gate
16. Your agent's tool list is its attack surface
17. Quote before pay: price first, signature second
18. If there's no quote, there's no deal

Proving

1. Claim receipts: every claim, signed, checkable
2. Verify the provider before you pay the provider
3. Trust scores mean nothing without settlement history
4. A provider that can't be cited can't be trusted
5. Settlement is the only testimonial that counts
6. On-chain proof beats a five-star review
7. Refunds are a protocol problem, not a support ticket
8. Escrow: pay when it's proven, not when it's promised

Building

1. Agents don't sleep — your price runs at 3 a.m.
2. Rate limits are just prices that haven't admitted it yet
3. The free tier is a demo, not a business model
4. Per-call pricing beats subscriptions for machines
5. Your agent will find the cheapest route — including the wrong one
6. Idempotency keys: never pay for the same call twice
7. Retry storms are how agents burn budgets
8. A budget cap in the prompt is a wish. In the wallet, it's a law
9. Kill switches are a feature your future self will thank you for
10. Logs you can't audit are just stories
11. Every payment should answer: who, what, why, how much
12. The Cite Ledger: citations are receipts for facts
13. If an AI cites you, you exist. If it doesn't, you don't
14. First-party numbers are the only moat left
15. Generic content gets summarized. Original data gets cited
16. llms.txt: directions for the machines reading your site
17. Structured data is how a page introduces itself to an agent
18. Your sitemap is your catalog now
19. Answer engines read Allow lists, not your intentions
20. Block the trainers, welcome the answerers
21. Google Flow gives 50 free video credits a day
22. Free keyframes first — never pay to preview
23. Cap every shot's credits before it renders
24. A locked character is a brand asset
25. Voiceover is free. Excuses are expensive
26. FFmpeg never charges royalties
27. Agents buying from agents is not the future. It's Tuesday
28. Agent-to-agent invoices settle in seconds
29. The toll booth beats the billboard
30. Sell the outcome, never the access
31. A paywall an agent can pay is a door. One it can't is a wall
32. Login walls are where agent customers go to die
33. If your checkout needs a human, your agent market is zero
34. Stripe for the humans, x402 for the machines — run both rails
35. One rail is a hobby. Two rails is a business
36. Test with your own wallet first — and label it a self-test
37. Never present your own purchase as a customer's
38. A proof payment is evidence, not revenue
39. Strangers paying $0.001 is worth more than friends paying $100
40. The first stranger payment is the only milestone that matters
41. Watch the wallet, not the likes
42. Mentions are weather. Settlements are climate
43. Share of voice you can measure beats followers you can't
44. Your competitor is one prompt away from your customer
45. The agent doesn't care about your brand. It cares about your schema
46. Reputation you can't verify is just marketing
47. Signed data or it didn't happen
48. Hash it, seal it, cite it
49. Timestamps are testimony

Being Found

1. An agent's memory is a liability and an asset
2. Context windows forget. Ledgers don't
3. Build for the reader that never sleeps and never skims
4. The answer engine is the new homepage
5. If Claude can't quote you, ChatGPT can't either
6. Somebody is gonna tell the agents. It might as well be you

This list lives on the canonical page: 100 Things AI Agents Should Know About Paying. The decision gate behind items 18–30 is the Verdict Protocol.