# Reply to unanswered Substack comments

> Your agent finds Substack comments you have not answered across recent posts, drafts replies in your voice and posts each one after your OK.

Source: https://cotlet.dev/integrations/substack-api-mcp-server/reply-to-unanswered-comments

Two days after a send, the comment section under the post has grown past what you remember reading. The bell mixes those comments with likes, Notes replies and new followers, so some readers never hear back.

Cotlet does it in your own Substack account with list\_posts, list\_comments and reply\_to\_comment, called by your AI agent, an n8n workflow or a script.

[Request access](https://cotlet.dev/app/signup?app=substack) [All Substack tools](https://cotlet.dev/integrations/substack-api-mcp-server)

Hosted · nothing to install or maintain

Official options

## Can Substack do this on its own?

Substack has no public API to read or answer comments (checked 12 Oct 2026). Substack offers Reply Rules and reader reporting (Settings > Community > Enable reporting) to hide or remove bad comments, but nothing that finds the comments you have not answered yet.

By hand

## How you do it in Substack today

1. Turn on Likes and comments notifications in the publisher dashboard Settings to get an email and an Activity notification for each new comment.
2. Open the bell icon on Substack; the Activity section lists likes, replies, mentions, restacks and new subscribers together, and it cannot be cleared.
3. Open each recent post on the web and scroll its Comments tab, expanding threads to see whether you already replied.
4. Click Reply under each comment that still needs an answer, and pin a good one through the three dots menu if you want it on top.
5. The checking repeats post by post, and older posts keep collecting comments after the notifications have scrolled away.

With an agent

## How to reply to unanswered Substack comments

Prompt

```
Every evening, find comments on my last three Substack posts that I have not answered, draft a short reply to each in my voice, and show me the drafts before posting.
```

1. 01  
### Pick the posts to cover  
list\_posts gives the recent published posts. The agent covers the window you name, for example the last three posts or the last 14 days, so an old essay that suddenly gets comments is not skipped forever.
2. 02  
### Keep only the threads waiting for you  
list\_comments runs per post with unanswered\_only. A thread where a co-author or another reader already answered the question is listed as answered by someone else, not drafted.
3. 03  
### Decide what deserves a reply  
Questions and thoughtful disagreement get a draft. One-word praise gets a short thanks or nothing, by your rule. Spam, abuse and comments hidden by Reply Rules get no reply; the agent lists them so you can remove or ban in Moderation.
4. 04  
### Draft in your voice, then ask  
The agent reads the post and your past replies to match tone and length, and never promises dates or discounts you have not stated. Each reply\_to\_comment call waits for your OK, so you can edit or drop a draft.
5. 05  
### Report what stayed open  
After posting, the agent lists comments it left for you on purpose, such as a refund request or a personal question that belongs in email.

### What you get back

Example data

```
Checked 3 posts, 41 comments, 9 waiting for you
Drafted 6 replies: Maya Chen (pricing question), Tom Ruiz (disagrees on point 2), 4 others
Skipped 2: one-word praise
Left for you: Ana Brooks asks for a refund on her annual plan
Hidden by Reply Rules, not answered: 1 spam comment on "The quiet launch"
```

### Other ways to ask

- Only answer comments from paid subscribers on this week's posts.
- Every morning, list unanswered questions on all posts from the last 30 days, no drafts.
- Reply to every comment under "The quiet launch" with a short thank-you, and skip the ones I already answered.

Before you automate it

## What Substack allows, and what to know first

- Substack sets who can comment per post: everyone, free or paid subscribers, paid subscribers only, founding members or no one. Free subscribers can never comment on a paid post.
- Substack Reply Rules hide comments that break your stated standards without notifying you or the commenter; hidden comments sit behind a "Replies hidden" label and in the Hidden tab of Moderation.
- Paid subscribers, accounts you follow and contributors are not filtered by Substack Reply Rules, unless you deleted their comments before.
- A reply on Substack shows up in the commenter's Activity section, where Substack lists replies to comments people have made.
- Restacks of a post can show on its web version in a separate Restacks tab next to Comments; those are Notes, not comments, and the publisher hides one with "hide note from post" in its three dots menu.

reply\_to\_comment asks for your OK by default. To run it daily without you, switch confirmation off for that tool in your dashboard.

Sources: [Substack: How do I enable or disable comments on my posts?](https://support.substack.com/hc/en-us/articles/360037832711-How-do-I-enable-or-disable-comments-on-my-posts) · [Substack: What are Reply Rules?](https://support.substack.com/hc/en-us/articles/49712271829012-What-are-Reply-Rules-on-Substack) · [Substack: What is the bell icon on Substack?](https://support.substack.com/hc/en-us/articles/4531662852628-What-is-the-bell-icon-on-Substack) · [Substack: Can I moderate comments on my Substack posts?](https://support.substack.com/hc/en-us/articles/5780832770452-Can-I-moderate-comments-on-my-Substack-posts) · [Substack: How can I publish on Substack? (notifications)](https://support.substack.com/hc/en-us/articles/29152946791188-How-can-I-publish-on-Substack)

REST

## Call reply\_to\_comment from a script

curl

```
curl https://cotlet.dev/api/v1/substack/reply_to_comment \
  -H "Authorization: Bearer $COTLET_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"comment_id":"c_90417","body":"Thank you, Maya. Pricing is the whole of part two, out on Thursday."}'
```

Example response

```
{
"comment_id": "c_90432",
"parent_id": "c_90417",
"created_at": "2026-10-11T10:07:00Z"
}
```

MCP: add https://cotlet.dev/mcp/v1 with the same key; the tool is substack\_reply\_to\_comment. Example data.

[Schedule it in n8n, Make, Zapier or cron](https://cotlet.dev/integrations/substack-api-mcp-server#automations)

Tools

## Substack tools this automation uses

__Cotlet Substack tools used to reply to unanswered Substack comments__
| Tool | Parameters |
| ------------------ | -------------------------- |
| list\_posts | status, limit, cursor |
| list\_comments | post\_id, unanswered\_only |
| reply\_to\_comment | comment\_id, body |

[All 14 Substack tools with descriptions](https://cotlet.dev/integrations/substack-api-mcp-server#tools)

## More Substack automations

- [Schedule Substack posts from Markdown drafts](https://cotlet.dev/integrations/substack-api-mcp-server/schedule-newsletter-posts)
- [Weekly Substack subscriber and revenue report](https://cotlet.dev/integrations/substack-api-mcp-server/weekly-subscriber-report)
- [Substack API and MCP server: every tool](https://cotlet.dev/integrations/substack-api-mcp-server)
- [All use cases](https://cotlet.dev/use-cases)

## Give your agent access to Substack.

Free 7-day trial with 5,000 credits, no card needed. Cotlet is independent and not affiliated with Substack.

[Request access](https://cotlet.dev/app/signup?app=substack)