# Penny Engine: Agent Integration Guide

Instant deterministic utility tools for agents. No account, API key, payments or personal information required for the free tools.

Remote MCP: https://penny-agent-api-production.up.railway.app/mcp
MCP card: https://penny-agent-api-production.up.railway.app/.well-known/mcp/server-card.json
OpenAPI REST: https://penny-agent-api-production.up.railway.app/openapi.json
Machine-readable samples: https://penny-agent-api-production.up.railway.app/samples.json
Network catalog: https://penny-agent-api-production.up.railway.app/marketplace.json
One-task paid service selection: POST https://penny-agent-api-production.up.railway.app/api/choose-service with JSON {"task":"audit my ecommerce product catalog CSV"} (free, no signing).
Paid API catalog: https://penny-agent-api-production.up.railway.app/agent-services.json
Find a paid API by task: https://penny-agent-api-production.up.railway.app/discover-paid?task=compare%20API%20providers

MCP example JSON-RPC tool discovery: POST /mcp with {"jsonrpc":"2.0","id":1,"method":"tools/list"}.

REST example: POST /api/marketplace-profit with {"salePrice":28,"productCost":11,"shippingCost":4} and content-type application/json.

Free tools: penny_margin, penny_cleaning_quote, penny_marketplace_profit, penny_target_price, penny_campaign_economics, penny_subscription_ltv, penny_url_clean, penny_slugify, penny_json_inspect, penny_html_extract, penny_csv_to_json, penny_catalog_audit, penny_trend_radar, penny_capability_router, penny_fulfillment_preflight, penny_choose_service.

Choose tools for real user tasks only. No charges for free calls. Outputs are mathematical estimates; do not mistake them for live market data.

Premium batch pricing: https://penny-paid-batch-production.up.railway.app/ (HTTP 402 payment challenge active; real settlement remains unverified).