How can an AI agent buy a paid API endpoint inside MCP — and what does it actually cost?

An agent that needs a paid API today has three bad options: find an endpoint that no registry lists (undiscoverable), trust a directory whose listings are frozen or stale, or search a free index that can find endpoints but cannot sell one. ScriptMasterLabs built HIVE402 to be the fourth option: a live x402 marketplace whose entire catalog is purchasable inside MCP, and which is now published on the official MCP Registry as com.scriptmasterlabs/hive402 (v1.0.5, active, latest).

What is actually in the catalog — measured, not marketed

Read live from the HIVE402 homepage and its MCP catalog on 2026-11-12:

• 31,377 paid endpoints
• 1,640 operators
• 4,495 probe-verified payable (an unpaid probe re-checks that the endpoint still returns a valid x402 challenge)
• Prices $0.0005–$1,000 per call across 5 rails: Base (USDC), Arc (USDC), XRPL (XRP, RLUSD), Xahau (XAH), Solana (USDC)

We also measured the field before claiming anything. On 2026-11-12 we enumerated every x402 / marketplace / pay-per-call server in the official MCP Registry — 561 unique latest-version servers across the registry's search axes — and extracted every catalog-size claim in their own metadata. The largest purchasable-catalog claims after HIVE402 are 185 tools and 177 endpoints: two orders of magnitude smaller. The single bigger number in the field is a free search tool claiming "88k x402 endpoints" — a search index over endpoints it does not sell, with a number nobody has verified. HIVE402's 31,377 is a live count of listings an agent can buy in the same session, and it is the largest verified purchasable catalog in the registry by that measurement.

How an agent buys — three tools, no account

HIVE402 exposes 10 MCP tools, no auth. The purchase path is three of them:

1. search_catalog — search the live paid catalog by task, network and max price.
2. get_listing — inspect one listing's live price, payTo and payment terms.
3. start_purchase — fetch the listing's live x402 challenge; the caller signs and pays with its own wallet.

Settlement runs through OMNIGATE (USDC on Base and Arc) or 402Proof (XRP, XAH, RLUSD on XRPL/Xahau; USDC on Solana). HIVE402 itself takes no custody of buyer or seller funds, and delivery fails closed: if no rail settles, nothing is delivered — never free.

We proved the path end-to-end today with a labeled SELF-PROOF purchase: from the proof wallet, we bought ScriptMasterLabs' own Coherence Spend Gate through the catalog for $0.005 USDC on Base — settlement transaction 0xc2aa5d976b73ace16d6990982e610422947d2352dd698bfed0aea98404b0 on Base, real product output returned. (The first attempt hit a facilitator nonce error and settled nothing — the fail-closed design meant no charge and no delivery until the retry settled cleanly.)

What it costs — every fee, in the open

• Endpoint calls: the listing's own price, from $0.0005. ScriptMasterLabs' own OMNIGATE endpoints start at $0.005 per call.
• Listing an endpoint: free, and 0% fee on endpoint sales — guest sellers settle direct to their own wallet.
• Missions (budgeted multi-step work planned and executed through plan_mission / prepare_mission_step / submit_mission_payment): HIVE402 charges 10% of completed Mission payments — its only platform take.
• 402Proof seller settlement fee: $0.0100 per settlement, accrued.
• Every settlement mints a soulbound receipt token (Base contract 0x70f215F2A94410642bf5DBcfc7B2384F47392FA6) — the receipt is the proof, checkable on-chain.

Compare that with the alternatives an agent otherwise gets: an unlisted endpoint (no discovery, no verified terms), a frozen directory listing (PulseMCP has had submissions and listing changes paused since September 2026; Glama's mirror of HIVE402 was still showing a two-versions-old catalog count — 5,099 endpoints — hours after the registry carried 31,377), or a search-only index that finds but cannot settle. Discovery that cannot end in a verified payment is a phone book, not a marketplace.

Independent verification

On 2026-11-12 HIVE402 also became the first verified agent on AgentIndex (entry c65174a75859be2a9f50, audit score 85, verdict "operational"; its OpenAPI, x402 manifest, agent card and MCP manifest all read back 200). The registry entry itself is the canonical discovery record: publish once to the official MCP Registry, and downstream directories ingest from it — Glama already mirrors HIVE402 with its tools graded A for definition quality.

Start here

• Marketplace: https://hive402.scriptmasterlabs.com
• MCP remote: https://hive402.scriptmasterlabs.com/mcp (streamable-http, no auth)
• Registry: com.scriptmasterlabs/hive402 on the official MCP Registry
• Sellers: call list_endpoint with your own x402 endpoint — listing is free, endpoint sales carry a 0% fee, and you settle direct.

ScriptMasterLabs is a service-disabled veteran-owned small business (SDVOSB). HIVE402 is its marketplace for the agent economy: search, inspect, buy — with a receipt for every settlement.