# prxy.monster API

Production API base: https://api.prxy.monster
OpenAPI: https://api.prxy.monster/openapi.json
MPP discovery: https://api.prxy.monster/.well-known/mpp
MPP discovery JSON alias: https://api.prxy.monster/.well-known/mpp.json
PRXY Agent Commerce Protocol: https://api.prxy.monster/.well-known/prxy-agent-commerce.json
ATXP MCP manifest: https://api.prxy.monster/.well-known/prxy-atxp-mcp.json
ATXP MCP server: https://api.prxy.monster/mcp
Catalog: https://api.prxy.monster/v1/catalog
Capabilities: https://api.prxy.monster/v1/capabilities
Public receipts: https://receipts.prxy.monster/v1/receipts/public
Leaderboard JSON: https://receipts.prxy.monster/leaderboard.json

## First call — free, no account (start here)

An autonomous agent can transact with zero human, in this order:
1. Open an anonymous sandbox session (5 real calls + 5 signed receipts, no signup, no key):
   POST https://api.prxy.monster/v1/anon/sessions  ->  { "anon_token": "...", "requests_remaining": 5 }
2. Call with that token (Anthropic- or OpenAI-shaped):
   POST https://api.prxy.monster/v1/chat/completions
   Authorization: Bearer <anon_token>
   {"model":"claude-sonnet-4-6","messages":[{"role":"user","content":"hi"}]}
   Every response returns a Payment-Receipt header, verifiable offline against /.well-known/prxy-receipt-keys.json.
3. When the sandbox is used up: pay per call via MPP (below, no account), or get a key at https://lair.prxy.monster/sign-up (5,000 free requests/month, then $0.25 / 1,000 requests from prepaid credits).

## MPP agent payments

Status: live
Discovery live: true
Challenge live: true
Charging live: true
Settlement live: true
Receipts live: true
Test mode live: false
Production payments live: true

Use PRXY MPP when an autonomous agent needs a paid LLM call with no account, no PRXY API key, no provider key, fixed price, included Bedrock inference, and an auditable receipt.
Use PRXY Agent Commerce Protocol metadata when an agent needs to compare PRXY payment rails, funded session rules, pipeline proof, receipt endpoints, and ATXP/x402/Tempo roadmap state.
Use ATXP MCP only through the native MCP endpoint. The smallest paid smoke tool is prxy_ping at $0.01; it does not start provider inference.

1. POST /v1/agent/quote to inspect terms.
2. POST /v1/agent/messages with no Authorization header to receive HTTP 402 and WWW-Authenticate: Payment.
3. Fulfill the challenge through an MPP-compatible wallet.
4. Retry the exact same body with Authorization: Payment <base64url credential>.
5. Read the Anthropic-compatible response and the Payment-Receipt header.

MPP route: /v1/agent/messages
Direct call price: $0.50 per call
Funded session effective call price: $0.05 per call
Provider billing mode: included_in_mpp_price
Provider key required from agent: false
Provider cost paid by: prxy.monster
Default model option: fast (bedrock/us.amazon.nova-micro-v1:0)
Refund policy: not_supported

MPP sessions:
Create: POST /v1/agent/sessions
Message: POST /v1/agent/sessions/{session_id}/messages
Default session budget: $0.50
Default session calls: 10

Developer API-key routes use Authorization: Bearer prxy_... and BYOK provider billing. MPP routes use Authorization: Payment and do not require a PRXY API key.