AI Guides › Step-by-step guides
By Nigel Guy · 9 min read
You post something useful, add "comment GUIDE and I'll send it over", and then spend the evening copying the same link into forty DMs one at a time. It feels like good community management. It is really a queue you have built for yourself, and it falls over the first day you are busy, ill or asleep in a different time zone from your audience.
The rule: let a keyword in the comment trigger the private message, so you only ever write the message once. Your own time then goes on the comments that need a human.
A comment-keyword auto-reply watches the comments under a post or reel. When a comment contains a word you choose, it sends that person one direct message, usually with a link, a download or a booking page. You can also have it leave a short public reply under the comment.
It suits you if you run an Instagram professional account (Business or Creator) and regularly offer something in exchange for a comment, such as a lead magnet, a price list, a sign-up link or a discount code. If you rarely get more than a handful of comments a week, skip the setup and keep replying by hand.
The mechanism is Meta's "private reply" feature. Meta's developer documentation sets two hard limits that every tool, free or paid, has to work within:
| Limit | What it means for you |
|---|---|
| One private message per comment | The automation gets one shot. If the commenter replies, a normal conversation opens and further messages are allowed. |
| Within 7 days of the comment | Comments on old posts will not trigger a DM later on. Turn the automation on before you publish, not a week afterwards. |
| Instagram Live: during the broadcast only | Comments on a live stream can only get a private reply while you are still live. |
Once someone replies to your DM or taps a button in it, tools like Manychat can send more messages in the following 24 hours.
| Meta Business Suite "Comment to message" | Manychat "Auto-DM links from comments" | |
|---|---|---|
| Cost | Free | Free tier, then paid by Active Contacts |
| Set up on | Desktop only | Browser or the mobile app |
| Which posts | Set within the template | A specific post, any post, or your next post |
| Public reply under the comment | Not described in Meta's help pages | Yes, up to three rotating versions |
| Extras | Pairs with Meta's other Inbox automations | Follow check, email capture, follow-up if the link isn't clicked |
| Catch | Meta's help pages describe the trigger as keywords in one place and hashtags in another; keyword matching is case-sensitive | The 25-contact free cap runs out after one busy post |
Start with Meta if you want something free and simple. Use Manychat if you also want email capture or a follow-up message.
Two Meta quirks to know. Custom keyword automations match exactly and are case-sensitive, so "Guide" and "guide" are different triggers. And if you turn on Meta Business Agent, your existing automations are paused.
PRICELIST rather than yes. Write it in capitals in your caption, and remember Meta matches case exactly.This prompt drafts that copy for you. Fill in the bracketed parts.
You are a copywriter for a small UK business that sends automated Instagram DMs when someone comments a keyword.
Context:
- Business and what we do: [BUSINESS_AND_OFFER]
- What the commenter asked for: [THE_THING_PROMISED]
- Link: [URL]
- Keyword in the caption: [KEYWORD]
- Our tone: [TONE, e.g. warm and plain, no exclamation marks]
Goal: copy that reads like a person wrote it and works even if it is the only message they ever receive.
Steps:
1. Write the main DM in under 60 words: say what this is, give the link, and add one line on what to do if the link does not open.
2. Write three different public comment replies, each under 12 words, that do not repeat the keyword and do not sound like a bot.
3. Write one follow-up message of under 30 words for people who did not click.
Rules: British English, no emoji, no false urgency, no claims about results. If any input above is missing or vague, ask me for it before writing anything.
Before you answer, check: is every message within its word limit, does the main DM still make sense without the other messages, and have you used any phrasing I would not say out loud? Fix anything that fails.
Paste in your business, the offer, the link, the keyword and your tone.
The trap is "any comment, any post". It feels thorough, and it turns your account into a vending machine that answers grief, complaints and jokes with a link. Close behind it are the free-tier contact cap (25 contacts disappear on one decent post) and the 7-day window, which means switching it on after a post has already taken off gets you nothing.
It won't read tone, handle a complaint, answer a follow-up question well, or work on a personal account. It won't reach someone after the 7-day window, and it won't make a weak offer interesting. It also does nothing for comments you never asked for, so keep reading those yourself.