Most API directories answer “what exists?” This page asks a different question: what still breaks when an AI agent has to discover, evaluate, pay for and verify an API without a human fixing the workflow?
Product names are weak routing keys. A machine buyer needs intent-level discovery: “turn this URL into Markdown,” “verify this provider,” or “get one stock quote.”
Better contract: publish exact jobs, aliases, inputs, outputs and current execution surfaces.Uptime alone does not tell an agent whether provider identity, machine metadata, payment terms or evidence are coherent.
Better contract: expose provider identity, runtime evidence and uncertainty before authorization.A cached page can advertise yesterday’s price while the executable endpoint has changed.
Better contract: treat the target’s fresh payment challenge as final executable authority.HTTP 402 means payment is required. A signature means authorization. Neither alone proves settlement or usable delivery.
Better contract: CHALLENGED → AUTHORIZED → SETTLED → DELIVERED → ACCEPTED.If a quote provider, page fetch or research source is unavailable, the buyer should not have to guess whether failure still consumes money.
Better contract: preflight where possible and define no-charge or non-accepted failure states explicitly.Research and verification outputs should preserve the source, timestamp and important limitations instead of returning a bare conclusion.
Better contract: return inspectable evidence with the answer.If the source URL is known, search is unnecessary overhead. If the source is unknown, one-page extraction is the wrong first step.
Better contract: route known URL → Markdown/extraction; unknown source → web research.One provider-backed quote is useful for speed. A higher-stakes claim may need multiple providers, disagreement, spread and evidence.
Better contract: separate quick quote from multi-provider verification.A reference-rate conversion can normalize budgets and reports, but it is not a tradable FX quote, settlement or custody.
Better contract: label rate source, timestamp, calculation role and execution boundary.An agent can discover an x402 API and inspect its payment requirements without giving the discovery layer unrestricted wallet authority.
Better contract: keep spend policy caller-controlled and the raw key outside the model/discovery boundary.These links show one implementation of the contracts above. They are evidence routes, not a claim that every competing product lacks the feature.
| Buyer problem | Narrow SML job | Why it is different |
|---|---|---|
| I know the public URL and need clean text. | URL to Markdown API | Known source → compact LLM-ready Markdown. |
| I know the URL but need structured output. | Web Scraping API | One-page extraction rather than whole-site crawl theater. |
| I do not know which source contains the answer. | Web Research API | Search + source evidence. |
| I need one current equity quote. | Stock Quote API | Small fast quote primitive. |
| I need stronger evidence that a market-data claim is right. | Market Data Verification | Provider disagreement and evidence stay visible. |
| I need to inspect a provider before dependency or spend. | Provider Trust / TrustBeforePay | Read-only pre-spend evidence. |
| I need a machine-readable reference-rate conversion. | Currency Conversion API | Reference conversion with explicit non-execution boundary. |
| I need to find x402 APIs and inspect payment requirements. | x402 Gateway | Discovery/preflight while caller controls spending. |
If several answers are missing, the integration has a gap even when the API itself works.
Open the Agent Buyer Console → · See buyer evidence → · Try jobs before paying →
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