Let your Hermes agent speak through any podcast app.

One MCP server. Text from your Hermes agent in, a published podcast episode out, in your favourite podcast app.

Apple PodcastsOvercastPocket CastsCastro
Hand this to your Hermes agent
Set up cast0 so you can create podcast episodes for me. Add it as a remote MCP
server to Hermes. URL: https://api.cast0.ai/mcp?key=${CAST0_API_KEY}

- Tell me to go to https://cast0.ai, get the API key in format pk_..., and paste it to you.
- Save it as CAST0_API_KEY (`hermes config set CAST0_API_KEY pk_...`).
- Reload MCP.
- Create short test episode so I can confirm it's working.

For more info, see https://cast0.ai/docs/connect-hermes
Or read the Connect Hermes docs.

Or skip reading. This page, made into a podcast by Hermes itself.

The Hermes pitch
The MCP that pitches itself. One prompt away.
0:56

One MCP. Three steps.

No backend to wire up. No file hosting. No RSS to publish. The MCP server does it all.

01

Your agent writes text

Briefing, research summary, weekly digest. Whatever your Hermes agent already produces.

02

MCP ships it to the cast0 API

One tool call from inside your agent. The cast0 MCP server handles auth, the API, and polling for completion.

03

Episode appears in your podcast app

Auto-published to your RSS feed. Apple Podcasts, Spotify, Overcast, anywhere you already listen.

Your Hermes agent writes too much to read.

You set up your agent to research, summarize, brief, digest. It does the work. The output piles up in chat scrollback. You read the first few lines and move on.

Audio fixes this. Episodes queue up while you sleep. The morning briefing waits in your podcast app next to The Daily. The research summary plays on your commute. The weekly digest catches you on a walk.

Your agent talks when it has something to say. You listen when you have time.

10,000words your agent writes a day
2,000words you actually read

Some content is better as a podcast.

Read this article as an episode...
→ ~9 min episode
Take this 50-page PDF and turn it into a 12-minute episode.
→ ~12 min episode
Research this topic and ship it to my podcast feed.
→ ~12 min episode
Pick 5 Hacker News stories matching my profile, weekday mornings.
→ daily, ~10 min
Every morning at 7am, summarize my inbox, calendar, and GitHub mentions.
→ daily, ~6 min
Turn that into a podcast
LIBRARY
Up Next
TODAY
Morning Briefing
6 min left
TODAY
HN Weekly Digest
12 min left
MON
Q1 Stripe MRR Recap & Outlook
9 min left
MON
Inbox Zero, Audibly
4 min left
SUN
Calendar this week
3 min left
Listen in

Pricing

$0
Free tier, generous enough to try.Or bring your own OpenAI key for unlimited.
$5/ mo
Pro, when your agent has more to say.

See full pricing.

Setup, end to end.

From zero to a published episode in about two minutes.

  1. 1

    Register the MCP server

    Use the prompt or CLI at the top of this page.

  2. 2

    Create a podcast and grab your API key

    Sign up at cast0.ai, name your podcast, pick a voice. Free, no card. The dashboard shows your API key (pk_...) and the RSS URL.

  3. 3

    Save the key in your Hermes config

    Store it as CAST0_API_KEY in ~/.hermes/.env (or run hermes config set CAST0_API_KEY pk_...). Hermes substitutes it into the MCP URL at connect time.

  4. 4

    Ask your agent to ship an episode

    Try: "Brief me on AI news from this week and ship it as an episode."

Full walkthrough with all three setup paths (prompt, CLI, config.yaml) in the Connect Hermes docs. The free tier covers about 40 minutes of audio per month. Need more? Paste your own OpenAI TTS key on the settings page and episodes stop counting against quota.

Common questions.

What does the MCP server actually do?
It gives your Hermes agent three tools to publish podcast episodes: create_episode, get_episode, list_episodes. Your agent calls create_episode with a title and the text, cast0 handles TTS and hosting, and the episode auto-publishes to your podcast's RSS feed.
Does it cost anything?
Free to start. The free tier covers 35,000 characters per month (about 40 minutes of audio on standard quality), with a 15,000 character cap per episode. Pro is $5/month for more monthly minutes and unlimited episode length. See cast0.ai/pricing for details, or paste your own OpenAI TTS key on the cast0 settings page to remove the cap entirely.
Do I need an OpenAI API key?
No. cast0 supplies the TTS by default. Bringing your own OpenAI key is optional, and removes the monthly cap.
Which podcast apps does it work with?
Any app that supports RSS feeds. Apple Podcasts, Spotify, Overcast, Pocket Casts, Castro. Each podcast gets its own unguessable feed URL you paste into the app.
Can my agent run this on a schedule?
Yes. Hermes supports scheduled tasks, so you can have your agent build a morning briefing at 7am and ship it as an episode automatically.
How long does generation take?
Asynchronous. Short episodes finish in under a minute, longer ones in a few. The MCP polls until the episode is ready and returns the audio URL.
Is there a length limit?
Per-episode cap of 15,000 characters on the free tier (about 17 minutes). With your own OpenAI key, no length limit. cast0 chunks and stitches long inputs into one seamless episode.
Can I keep my podcast private?
Yes. The RSS URL contains an unguessable token, not a slug. Share with whoever you want, or keep it entirely to yourself.
Can I change the voice?
Yes. Each podcast has its own voice and speed setting. Any OpenAI TTS voice works. Change it any time from the dashboard.
What languages are supported?
OpenAI TTS supports 57 languages including English, Spanish, French, German, Japanese, Portuguese, Chinese. Send text in any of them.
Where do I find the full setup docs?
See the Connect Hermes docs. Three setup paths: prompt the agent, run hermes mcp add, or edit ~/.hermes/config.yaml directly.

Give your Hermes agent
a voice.

One MCP. Real RSS. Episodes in the podcast app you already use.

Hand this to your Hermes agent
Set up cast0 so you can create podcast episodes for me. Add it as a remote MCP
server to Hermes. URL: https://api.cast0.ai/mcp?key=${CAST0_API_KEY}

- Tell me to go to https://cast0.ai, get the API key in format pk_..., and paste it to you.
- Save it as CAST0_API_KEY (`hermes config set CAST0_API_KEY pk_...`).
- Reload MCP.
- Create short test episode so I can confirm it's working.

For more info, see https://cast0.ai/docs/connect-hermes
Or read the Connect Hermes docs.