Post to Lemmy from ChatGPT

ChatGPT drafts it. You approve it. PostDelegate posts it.Lemmy: Posts to one or more communities on your instance.

How to post to Lemmy from ChatGPT

Add PostDelegate to ChatGPT. In ChatGPT open Settings, then Connectors, then Create. If you cannot create one, look for a developer mode switch under advanced settings, or ask your workspace admin. Name it PostDelegate, paste the server URL below and choose OAuth. Choose Create, then Connect, sign in to PostDelegate and click Authorize.
Server URL
```
https://app.postdelegate.com/mcp-oauth-dynamic
```
Custom connectors depend on your ChatGPT plan and workspace settings, which OpenAI controls.
Connect Lemmy in PostDelegate. On the calendar page choose Add Channel, then Lemmy. Enter the instance address starting with http:// or https://, your username or email, and your password. PostDelegate signs in to the instance and shows your account on the channel.
Ask ChatGPT for a draft. Describe the post in plain words. ChatGPT checks your Lemmy channel's rules, creates the post and sends back a preview link.

Teach ChatGPT the posting rules

Paste the PostDelegate instructions into a custom GPT or a Project, with the connector enabled there, so ChatGPT follows the posting rules in every chat. Agent files has the steps.

What to ask ChatGPT

Mention any Lemmy setting in plain words and ChatGPT fills it in. Start with something harmless, like asking which channels you have.

Draft a Lemmy post for the selfhosted community with the title “We open-sourced our scheduler” and a link to the repository.
Post the same announcement to two communities, each with its own title, as drafts.

What ChatGPT can do on your Lemmy channel

Check the rules first. Before writing, it reads your Lemmy channel's length limit (10,000 characters) and required settings.
Draft, schedule or post. It creates a draft, a scheduled post or an immediate post, and runs the same checks as the app.
Use your media. It attaches files from your media library or adds one from a public link.
Review and fix. It lists what is scheduled, changes the Lemmy settings of a post that has not gone out, and deletes posts you no longer want.

Lemmy is made of separate instances, so PostDelegate asks which one you use, for example https://lemmy.world, along with your username or email and password. Each post goes to one or more communities, and every community needs its own title.

Lemmy settings ChatGPT can fill in

Setting	Notes
Community	Required. Choose one or more communities. Each one needs its own title.
Title	Required, at least 2 characters, one per community.
URL	Optional link to attach to the post.

Before you start

Lemmy has no app passwords, so you connect with your real account password. It is encrypted before it is stored.
A post fails with a readable reason if your account is banned, the community no longer exists, or the instance blocks a link in the post.

The Lemmy channel guide has every field, and MCP tools lists exactly what an assistant can and cannot do.

Questions

Will ChatGPT publish to Lemmy without asking me?

Not unless you ask it to. Ask for a draft and the post waits on your calendar until you schedule it, and your workspace's approvals apply as usual. Tools that change data are marked as such, so ChatGPT can ask you before it schedules or deletes anything.

Do I need an API key to connect ChatGPT?

No. ChatGPT signs in with your PostDelegate account through your browser. An API key is only for clients that cannot sign in, as described in MCP clients.

Does it cost extra to use ChatGPT with PostDelegate?

No. The MCP server is on every plan, and ChatGPT runs on your own ChatGPT account, so PostDelegate never charges for AI. Every plan starts with a 7-day free trial with no card.

Can ChatGPT attach images or video to a Lemmy post?

It can use files already in your media library, or add one from a public link. It cannot fetch files from your computer, so upload those in the app first, or through the upload widget where ChatGPT shows it. See MCP tools.

Can I post to several Lemmy communities at once?

Yes. Choose one or more communities in the Community setting. Each community needs its own title, so the same post can be titled differently for each one.

Is my Lemmy password stored?

Lemmy has no app passwords, so you connect with your real account password. It is encrypted before it is stored, and you can change it later with Update Credentials in the channel's menu.

Lemmy from other assistants

Other networks from ChatGPT

Prefer to plan Lemmy posts yourself? See the Lemmy scheduler.