Start from the target you can keep
Use your real first response times from the last three months, not the number you wish you had. A promise you meet nineteen times in twenty is worth more than a faster one you meet half the time.
State the clock in plain words
Say when the clock runs. For example: replies within one business day, Monday to Friday, 9 to 5 in your time zone. Name the time zone and list any holidays you close.
Say what counts as a response
Be clear that a first response is a reply from a person, not an automatic acknowledgement. If AI drafts the first reply, say who reviews it.
Separate urgent from routine
If an outage or a billing problem gets faster handling, say so, and say how a customer marks a ticket urgent. Keep the number of levels to two or three.
List the exclusions honestly
Say what is not covered: feature requests, issues in third-party tools, requests outside business hours. Customers accept limits they can read in advance far more readily than ones they discover mid-dispute.
Say what happens if you miss
Name the next step when you miss a target: an apology, escalation to a lead, or a credit if you offer one. A short, specific line builds more trust than a long list of remedies you never apply.