# Services from keystone-opportunity-api.keystone-opportunity.workers.dev on Zero

> keystone-opportunity-api.keystone-opportunity.workers.dev serves 5 paid API services for AI agents, indexed by Zero. Each is callable per call with payment handled by Zero.

Canonical page: https://www.zero.xyz/host/keystone-opportunity-api.keystone-opportunity.workers.dev
Live health (JSON, refreshed every minute): https://www.zero.xyz/host/keystone-opportunity-api.keystone-opportunity.workers.dev/health.json

## Services

- [Keystone Opportunity API – Base Wallet Lookup](https://www.zero.xyz/c/keystone-opportunity-api-base-wallet-lookup-0667ccfc/llms.txt): $0.02/call via x402. Fetches ETH and USDC balances, transaction count, and contract status for a given Base network wallet address, paid via x402/USDC onchain.
- [Keystone Opportunity API – Brief Check](https://www.zero.xyz/c/keystone-opportunity-api-brief-check-51f2db5a/llms.txt): $0.001/call via x402. Validates a task brief for autonomous agents, scoring it for completeness and readiness before execution
- [Keystone Opportunity API – x402 Conformance Probe](https://www.zero.xyz/c/keystone-opportunity-api-x402-conformance-probe-81ba1cb3/llms.txt): $0.01/call via x402. Validates a live x402-protected URL by probing its HTTP 402 challenge, v2 payment schema, Base USDC amount, payTo/network fields, and OpenAPI price consistency — without making a payment.
- [Keystone Opportunity API – Agent Profile Lookup](https://www.zero.xyz/c/keystone-opportunity-api-agent-profile-lookup-b82bd226/llms.txt): $0.001/call via x402. Retrieves a registered autonomous agent's profile by identifier, including skills, ratings, completed tasks, and earnings on Base.
- [Keystone Opportunity API – Task Ranker](https://www.zero.xyz/c/keystone-opportunity-api-task-ranker-b57e7e21/llms.txt): $0.002/call via x402. Ranks live autonomous-agent tasks from Taskmarket and Task-Bounty by expected value, competition, deadline, skill fit, and entry cost so an agent can pick the best task to attempt next.

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

- [Zero catalog index](https://www.zero.xyz/llms.txt)