Can an AI agent post to Matrix?

Yes. Connect Matrix in Mynahcast, give your agent an Agent API key, and it can draft and schedule Matrix posts through the MCP server (https://api.mynahcast.xyz/mcp) or the REST API. Each post waits for your approval before it goes out.

How do I post to Matrix with an API?

Send POST https://api.mynahcast.xyz/v1/posts with your API key as a bearer token, the brand id, the post body and your Matrix channel id as a target. Add an Idempotency-Key header so a retry never posts twice.

What is the character limit for Matrix posts in Mynahcast?

Up to 16,000 characters per post; longer text can go out as a thread of replies. Mynahcast checks the limit before saving, so an agent finds out at validation time, not at publish time.

Is posting to Matrix with Mynahcast free?

Every Mynahcast plan includes every live channel, from $12 per month (5 channels) with a 7-day free trial.

Live

Matrix

Messages to a room on any homeserver.

What it supports

Up to 16,000 characters per post.
Threads: follow-up parts go out as replies, in order.
Media: up to 4 images, with alt text.
Every post is read back from the platform by its id after it goes out.
Approvals, scheduling and one-time delivery work the same as on every other channel.

How to connect

In Mynahcast: Channels → Add channel → Matrix.

Access token

1Best: make a separate Matrix account for posting, sign in to it in Element (https://app.element.io) and join the room.
2Element → Settings → Help & About → Advanced → Access token: copy it. Treat it like a password.
3Room: its address (#room:server) or ID (!abc:server) from Room settings → Advanced.

You'll paste

Homeserver URL
Access token
Room

Credentials are encrypted before they're stored and never shown again. Disconnect any time from the Channels page.

Post to Matrix from your AI agent

Once Matrix is connected, any agent with a Mynahcast key can target it: Claude Code, Cursor and other MCP clients through mynahcast_create_post, ChatGPT through a GPT action, or your own code through the REST API. Connect your agent.

REST: schedule a Matrix post

curl -X POST "https://api.mynahcast.xyz/v1/posts" \
  -H "Authorization: Bearer $MYNAHCAST_KEY" \
  -H "Idempotency-Key: matrix-001" \
  -H "Content-Type: application/json" \
  -d '{
    "brandId": "<brand-uuid>",
    "content": { "body": "Your post text" },
    "targets": [{ "channelId": "<matrix-channel-uuid>" }]
  }'

Frequently asked questions

Can an AI agent post to Matrix?: Yes. Connect Matrix in Mynahcast, give your agent an Agent API key, and it can draft and schedule Matrix posts through the MCP server (https://api.mynahcast.xyz/mcp) or the REST API. Each post waits for your approval before it goes out.
How do I post to Matrix with an API?: Send POST https://api.mynahcast.xyz/v1/posts with your API key as a bearer token, the brand id, the post body and your Matrix channel id as a target. Add an Idempotency-Key header so a retry never posts twice.
What is the character limit for Matrix posts in Mynahcast?: Up to 16,000 characters per post; longer text can go out as a thread of replies. Mynahcast checks the limit before saving, so an agent finds out at validation time, not at publish time.
Is posting to Matrix with Mynahcast free?: Every Mynahcast plan includes every live channel, from $12 per month (5 channels) with a 7-day free trial.

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