Limits and cost
Rate limits, token lifetime, and what a tool call costs.
Tokens last an hour. Clients that only hold a header will start getting 401s when it expires; re-mint from the client credentials, which don't expire unless you set an expiry or revoke them.
Rate limits are the API's, shared with everything else the company does through the API. A tool call spends two requests against that budget — one for the MCP call, one for the API call it makes — so plan for roughly half the throughput you'd get from the REST API directly.
Usage counts. Tool calls appear in the request counters on the API page like any other API traffic.
Results are capped at 50 records per call, and trimmed further if a page would be enormous. When that happens the result says so — a truncated answer never pretends to be complete.