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Deep-dive 14 min read

Prompt architectures for SMS: tone, length, and timing

System + role + memory + tools. What wins in production and what silently burns credits.

Product Team
MyChatBot
May 18, 2026

Why SMS punishes a wordy agent

SMS strips away everything you can lean on elsewhere, no images, no buttons, no formatting, and a hard character budget. Every word has to earn its place, and one clumsy text reads as spam. A verbose prompt that works in chat produces bloated, robotic SMS. Architecture is what makes an agent concise, warm and on-time.

No images, no buttons, a hard character budget, every word has to earn its place
No images, no buttons, a hard character budget, every word has to earn its place

The four layers

MyChatBot agents stack in layers. System sets a tight, human voice and a brevity rule. Role narrows the job, reminders, reactivation, qualification. Memory is the Knowledge Base plus CRM history, so the agent answers from facts and remembers the person. Tools is where it acts, CRM writes, bookings. The brevity discipline lives in the system layer so every reply stays short.

Writing for 160 characters

Concision is a design constraint, not an afterthought. The system layer instructs the agent to answer in one clear thought, lead with the useful part, and drop filler. Agentic Search supplies the single fact the text needs, so the agent never pads a message to sound complete. Short, specific, human, that is the whole craft of SMS.

Timing is part of the prompt

On SMS, when you send is as important as what you send. The architecture ties message timing to behavior via Follow-ups and CRM Labels & Statuses, so a text lands when it is welcome, not at 2am or one too many times. Good timing is the difference between a reply and a STOP.

What silently burns credits, and shipping it

The quiet budget killers: re-loading context per text and over-long generations. Fix it with narrow retrieval, CRM memory, and a strict brevity rule, which also makes the SMS better. Then ship via the Configuration Wizard, which battle-tests and versions every change, and set Hand-off Control with Flight Control in Telegram so the agent escalates cleanly.

#sms#prompts#architecture
Product Team
MyChatBot

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