# Machine Library A2A Agent

**Canonical:** https://apis.io/apis/machinelibrary-ai/machine-library-a2a-agent/  
**Provider:** Space Frontiers — https://apis.io/providers/machinelibrary-ai/  
**Base URL:** https://machinelibrary.ai/a2a  
**Documentation:** https://machinelibrary.ai/.well-known/agent-card.json

Machine Library A2A Agent is one of 4 APIs that [Space Frontiers](https://apis.io/providers/machinelibrary-ai/) publishes on the [APIs.io](https://apis.io/) network. Tagged areas include A2A, Agent-Native, Research, and Payments. The published artifact set on APIs.io includes API documentation.

A2A (protocolVersion 0.3.0) research and commerce agent at https://machinelibrary.ai/a2a over JSON-RPC: grounded research answers with citation artifacts, search-access guidance, and prepaid-credit sales settled through Stripe (ACP checkout sessions and MPP payment challenges), with two AP2 merchant-role extensions declared. The agent card is served at /.well-known/agent-card.json on machinelibrary.ai and spacefrontiers.org. Unauthenticated message/send is answered live with authentication guidance.

## Machine-readable artifacts (2)

- **AgentCard** — https://raw.githubusercontent.com/api-evangelist/machinelibrary-ai/refs/heads/main/a2a/machinelibrary-ai-a2a.yml
- **Documentation** — https://api.machinelibrary.ai/auth.md

## Other Space Frontiers APIs (3)

- [Machine Library API](https://apis.io/apis/machinelibrary-ai/machine-library-api/)
- [Machine Library MCP Server](https://apis.io/apis/machinelibrary-ai/machine-library-mcp-server/)
- [Hermes Search Engine gRPC API](https://apis.io/apis/machinelibrary-ai/hermes-search-engine-grpc-api/)

## Tags

A2A, Agent-Native, Research, Payments

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/apis/machinelibrary-ai/machine-library-a2a-agent/). The API's provider profile, Kin Score and agent-readiness rating are at https://apis.io/providers/machinelibrary-ai/.