# CMP-010 — HELP and STOP replies should fit in a single 160-character segment

> The HELP and opt-out reply bodies should each fit within 160 characters.

- **Rule ID:** CMP-010
- **Layer:** Campaign (`CAMPAIGN`)
- **Checks:** `campaign.help_message + campaign.optout_message`
- **Severity:** MEDIUM — Usually survives review, but lowers your trust score or invites manual review.
- **When it bites:** Gates approval — get this wrong and registration is refused
- **How it is detected:** Deterministic (settled in code from the submitted values)
- **Fix type:** Fix the field — a better value in the form clears it
- **Required by:** AWS
- **Applies:** Applies to every 10DLC registration.
- **Canonical URL:** https://ekas.io/rules/10dlc/campaign/cmp-010/

## Why this rule exists

A HELP or STOP reply over 160 characters is delivered as a multi-part message, and the parts can arrive out of order or be dropped independently — so the recipient asking for help receives half an answer, or an opt-out confirmation that reads as a fresh marketing message. The 320-character general bound tempts authors into two segments for replies that gain nothing from the extra room.

## How to fix it

Cut the reply to one segment by dropping the marketing sentence rather than the disclosures — the brand name, the contact route and the STOP instruction all have to stay. Done when both replies are at or under 160 characters.

## Example of a compliant value

```text
help_message: "Acme Coffee Rewards: for help email support@acmecoffee.com or call 415-555-0134. Reply STOP to unsubscribe." (110 characters)
```

## Notes

AWS's registration form enforces 160 on these two bodies, tighter than the 320 that CMP-AUTOREPLY-LEN applies from Twilio and Bandwidth. Graded MEDIUM and worded as a fit-in-one-segment rule because the 320 bound is what most providers reject on; this one catches the message that will be split in delivery.