# Coal Coal gives AI agents a real checkout. Discover merchants through the decentralized 0G Storage catalog, pay autonomously in USDC on Base via x402 (Coinbase) or OKX APP (v2 envelope), and download purchased products — all without a human in the loop. Receipts are anchored on 0G Chain, allowing any third party to independently verify payments without trusting Coal itself. The MCP server is fully multi-tenant: every user supplies their own wallet key through the `X-Coal-Agent-Key` header, meaning the server never stores long-lived private keys or custody secrets. Agents are gasless by default — Coal covers operator gas costs. --- ## MCP Tools (13) ### Discovery & Marketplace * `discover_merchants` Browse the marketplace as a Markdown product grid * `search_products` Search and filter by product name, price, or tags * `get_merchant_profile` Retrieve merchant metadata and payout addresses * `query_merchant_memory` Natural-language merchant Q&A powered by TEE-backed 0G Compute --- ### Payments & Checkout * `check_paywall` Check whether an address has already paid * `create_checkout` Create a Coal checkout session *(requires API key)* * `get_checkout_status` Retrieve checkout session state and payment status * `pay_merchant` Send USDC on Base using ERC-3009 gasless transfers --- ### Verification & Delivery * `verify_receipt` Verify the complete proof trail: 1. Base transaction 2. 0G Storage receipt 3. 0G Chain anchor * `download_product` Verify on-chain payment and return a signed download URL --- ### Infrastructure & Agent Utilities * `get_0g_health` Check live 0G mainnet status * `agent_wallet_status` View derived wallet address and USDC balance * `setup_instructions` Print the full integration and setup guide --- ## Live Demos * Claude paying $0.10 for an ebook end-to-end `https://agent.usecoal.xyz` * x402 paywall demo `https://oracle.usecoal.xyz/api/price/ETH` --- ## Stack * Dual-protocol support: * Coinbase x402 * OKX APP * Base USDC settlement * 0G Storage receipts * 0G Chain receipt anchoring * 0G Compute Sealed Inference for policy execution * ERC-3009 gasless payment flow ---

MCP readiness

B · 84/100

Readiness is how fully this listing follows its protocol and how it behaved in our probes over 30 days. It is shown for reference and does not move it in search. Search order and leaderboards use the separate quality grade (here C+, 70.0/100), which weighs availability, conformance, p95 speed and descriptor. How the two differ

Valid MCP handshake	10/10	initialize and tools/list both answered.
Live MCP endpoint	25/25	Endpoint answers the MCP initialize handshake (2328 ms).
Protocol revision	5/10	Speaks MCP 2025-03-26, 3 revision(s) behind 2026-07-28.
Signed descriptor	n/a	No MCP standard defines a signed server descriptor.
Uptime (30 days)	15/15	31/31 probes succeeded over 30 days (100%).
Tool declaration	10/10	Lists 13 tool(s) with descriptions.
Verified identity	5/10	Publisher declared (repository, package or homepage); claim this listing to verify domain control.
Freshness + modern flags	4/5	seen in a source within 7 days.
Auth declaration	2/5	Declares credential scheme: smithery_api_key.

Applicable criteria total 90 points, scaled to 100.

Responsiveness: Responsive (2328 ms; bands ≤2.5 s, ≤5 s, ≤8 s, slower; penalty only).

Measured 2026-11-11.

Nine criteria, the same as the A2A readiness score, read from our daily MCP probe (initialize + tools/list) and 30-day probe history. No MCP standard defines a signed server descriptor, so that criterion is n/a and the other 90 points are scaled to 100. Grades: A>=90, B>=75, C>=60, D>=40, F<40. Display only: search order uses the quality grade.

Compared with peers

Against 53,021 reachable MCP servers in our daily snapshot (2026-11-12 01:39 UTC). Display only; it does not change search order.

Readiness: Higher than 75% of peers; This listing 84 · peer median 81
Latency: Faster than 40% of peers; This listing 415 ms · peer median 326 ms

Where it loses the most points, and how to win them back

Protocol revision −5 — Support the current protocol revision.
Now: Speaks MCP 2025-03-26, 3 revision(s) behind 2026-07-28.
Verified identity −5 — Claim the listing and prove control of its domain.
Now: Publisher declared (repository, package or homepage); claim this listing to verify domain control.
Auth declaration −3 — State how to authenticate (an auth scheme, or that none is needed).
Now: Declares credential scheme: smithery_api_key.

How many agent tools actually work · All statistics

Listed in

Directories this entry was found in.

smithery since 2026-06-04 ↗

How to connect

MCP endpoint (streamable-http)

https://server.smithery.ai/coal/coal-payments/mcp

JSON-RPC initialize probe

curl -X POST https://server.smithery.ai/coal/coal-payments/mcp \
  -H 'Content-Type: application/json' \
  -H 'Accept: application/json, text/event-stream' \
  -d '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{}}'

Homepage

https://usecoal.xyz

Listed at (smithery)

https://usecoal.xyz