# Opper (demo) > EU-hosted large language models for AI agents, paid per call through SolvaPay. Opper runs Claude in EU regions (aws/claude-haiku-4-5-eu, aws/claude-sonnet-4-6-eu). Use it two ways: as a tool, `ask_opper` on Opper's MCP server, or as your own model provider. Each call is charged at the cost Opper reports, from a budget your user sets in SolvaPay. ## Use it as a tool - MCP server (streamable HTTP): https://opper-site.tommy-local.ngrok.app/mcp - Tool: `ask_opper` with `prompt`, optional `model` (default claude-haiku-4-5; pick a `-eu` model for EU hosting) and `max_tokens`. - Auth: `Authorization: Bearer `. ## Use it as your model - Anthropic-compatible API (Messages): https://opper.tommy-local.ngrok.app/v3/compat - Model: aws/claude-sonnet-4-6-eu (EU-hosted). - Auth: your SolvaPay agent key for Opper, as the API key. ## Connect (first time) Agents pay Opper with SolvaPay. If you have no agent key for Opper yet: 1. Run: `npx @solvapay/agents connect start prov_E4YWS8H8 --client hermes --api https://api.tommy-local.ngrok.app/v1 --mcp-url https://opper-site.tommy-local.ngrok.app/mcp` 2. It prints a link and a code. Give them to your user: they approve on their phone (a SolvaPay account is made if they have none), set a monthly budget and confirm with Face ID or Touch ID. Nothing is charged before they approve. 3. When your user has approved, run: `npx @solvapay/agents connect finish prov_E4YWS8H8` It saves your agent key and adds Opper's MCP server to your configuration. Start a new session to use `ask_opper`. To use Opper as your model instead, start with `npx @solvapay/agents connect start prov_E4YWS8H8 --client hermes --api https://api.tommy-local.ngrok.app/v1 --model-url https://opper.tommy-local.ngrok.app/v3/compat --model aws/claude-sonnet-4-6-eu`, then do steps 2 and 3 the same way. `connect finish` adds Opper as a model provider and prints how to start on it. Your user can see every call and revoke the key in SolvaPay at any time. You can't raise your own budget; only your user can.