# CMP-SAMPLE-LEN — Each sample message must be 20–1024 characters

> Every sample message must be at least 20 and at most 1024 characters.

- **Rule ID:** CMP-SAMPLE-LEN
- **Layer:** Campaign (`CAMPAIGN`)
- **Checks:** `campaign.sample[]`
- **Severity:** BLOCKING — Breaking this rule gets the submission rejected outright.
- **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:** Twilio, TCR
- **Applies:** Applies to every 10DLC registration.
- **Canonical URL:** https://ekas.io/rules/10dlc/campaign/cmp-sample-len/

## Why this rule exists

A sample under 20 characters cannot demonstrate a real message, and one over 1024 is not a text message at all. Both bounds are published and enforced mechanically at submission.

## How to fix it

Write realistic sample messages of at least 20 characters each.

## Example of a compliant value

```text
Acme Coffee: 20% off all beans this weekend. Reply STOP to opt out, HELP for help.
```