feat: add Arkham Intelligence API (x402)

[ironjaaan]

Adds Arkham Intelligence's blockchain-intelligence API at https://api.arkm.com/x402 to the registry.

What it offers

91 endpoints (88 paid, 3 free SIWX) of Arkham's read API under pay-per-request USDC via x402 v2 — same data and response shapes as the subscription Arkham API: entity and address attribution (who owns a wallet), balances and portfolios, transfer and exchange-flow tracing, swaps, token holders and market data, and Polymarket analytics across 10+ chains. No account, no API key; agent instructions live at /skill.md.

Multi-chain

Every 402 challenge advertises both Solana mainnet and Base mainnet USDC. On Solana the fee payer is covered — agents need no SOL. Settlement happens only after a successful upstream response, so failed requests are never charged.

Pricing

Prices are embedded per operation in the OpenAPI (x-payment-info). Most lookups are a flat $0.20; per-row endpoints (transfers, swaps) price by the requested limit; premium batch intelligence costs more. The free SIWX routes (chains, networks/status, arkm/circulating) cover orientation.

Validation

$ pay catalog check providers/arkham/api/PAY.md
PAY.md check successful
91 endpoints tested across 1 provider
88/88 gates compatible with Solana

The committed openapi.json is a verbatim snapshot of https://api.arkm.com/x402/openapi.json.

[greptile-apps]

Greptile Summary

Adds Arkham Intelligence as a payment-gated API provider.

• Defines provider metadata, routing guidance, payment behavior, and spend-aware usage in PAY.md.
• Adds an OpenAPI 3.1 snapshot covering 91 blockchain-intelligence endpoints with x402 pricing and SIWX authentication metadata.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains.

Important Files Changed

Filename	Overview
providers/arkham/api/PAY.md	Adds valid registry metadata and agent-facing usage guidance for the Arkham API.
providers/arkham/api/openapi.json	Adds the Arkham API contract; the previously reported time-window, token-identifier, and Solana-example defects are corrected in the current version.

_{Reviews (7): Last reviewed commit: "feat: add Arkham Intelligence API (x402)" | Re-trigger Greptile}

[ironjaaan]

hi @lgalabru! any chance of a review here when you have a moment? everything passes locally and happy to fix anything that comes up. thanks for the work on this registry 🙏