Install the Nevermined Payments SDK and create a Plan in the Nevermined console that defines your pricing model (credits per tool call, subscription tier, or pay-per-use rates)
Wrap each MCP tool handler with the Nevermined payment middleware; before executing the tool, the middleware calls the Nevermined API to verify the requesting agent holds a valid subscription or sufficient credits for the operation
If the agent's balance is insufficient, the middleware returns an MCP error response with a payment-required code and the Nevermined checkout URL so the agent or its principal can top up
On successful credit verification, decrement the agent's balance atomically and proceed with tool execution; return the tool result along with the remaining credit balance in the MCP response metadata
Monitor usage and revenue in the Nevermined console; configure webhook alerts for low-balance agents and automated suspension when balances reach zero
Known gotchas
The credit decrement and tool execution are not atomic across Nevermined and your tool backend; if your tool errors after credits are deducted, you must implement a refund or retry credit via the Nevermined API to avoid charging for failed calls
Nevermined's middleware adds a network round-trip for credit verification on every tool call; for latency-sensitive tools, consider batching credit verification or using pre-purchased session credits to avoid per-call overhead
Different MCP client implementations handle payment-required errors differently; test that your target agent frameworks (Claude, GPT-4, LangChain) correctly surface the top-up URL to the user rather than silently swallowing the error
Give your agent this knowledge — and 200+ more routes
One MCP install gives any agent live access to the full route map, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp