Model Context Protocol

Introduction

Model Context Protocol is part of the Paycux platform. This page explains what it does, when to reach for it, and the smallest working setup you can ship.

Everything below applies to both environments. Build and test in staging, then promote the same configuration to production without changing your code — only the API key and client ID differ.

Authorization

Every API request is authenticated with a bearer token in the Authorization header. Keys are scoped to a single environment and are shown once at creation — store them in a secret manager, not in source control.

1curl -X GET 'https://api.paycux.com/v1/organizations' \
2  -H 'Authorization: Bearer $PAYCUX_API_KEY'

Integrating

Integrating is handled by Model Context Protocol rather than by your application code. Paycux exposes it through the same API surface as the rest of the platform, so the client you already configured needs no additional setup.

Configuration lives in the dashboard and is versioned per environment. Change it in staging, confirm the behaviour, then apply the same change to production.

Enabling Client ID Metadata Document (CIMD)

Paste the provider's metadata URL into the connection. Paycux reads the signing certificate and endpoints from it and re-reads them on a schedule, so a certificate rotation does not break the connection.

Configure MCP Server URL

Configure MCP Server URL is handled by Model Context Protocol rather than by your application code. Paycux exposes it through the same API surface as the rest of the platform, so the client you already configured needs no additional setup.

Configuration lives in the dashboard and is versioned per environment. Change it in staging, confirm the behaviour, then apply the same change to production.

Set a default Resource Indicator

Set a default Resource Indicator is handled by Model Context Protocol rather than by your application code. Paycux exposes it through the same API surface as the rest of the platform, so the client you already configured needs no additional setup.

Configuration lives in the dashboard and is versioned per environment. Change it in staging, confirm the behaviour, then apply the same change to production.

Token Verification

Access tokens are JWTs signed with a rotating key. Verify them against the JWKS endpoint for your client rather than a pinned public key, so rotation never causes an outage.

1https://api.paycux.com/sso/jwks/client_01M4KXD1PZXFWGWE9ZKPCQRAQ

Cache the key set and re-fetch on an unknown key ID. Reject any token whose issuer, audience or expiry does not match what you expect.

Metadata

Metadata applies specifically to Model Context Protocol. It behaves the same in both environments, and the values it depends on are visible in the dashboard for the environment you have selected.

If the behaviour you see does not match this description, check which environment your API key belongs to before anything else — a staging key against production data is the most common cause.