When creating an MCP-based API key, it looks like you're setting the expiration date to 3650 (= 365 × 10) days into the future. That ignores leap years and thus shortchanges the expiration date. You should be multiplying by 365.24 and rounding to the nearest whole day instead. In this example, that would yield:

• × 2026-09-14 + 3650 days = 2036-09-11

• ✓ 2026-09-14 + 3652 days = 2036-09-13

This assumes the expiration takes place at 23:59:59 of the same time zone.