Live AI co-hosts, on demand
Every stream needs a counterparty.
Counterparty is building a cast of AI co-hosts that streamers and podcasters invite onto their streams on demand. Each one is an original character with its own personality, voice and face, there to debate, run games for chat, play along, tell stories or keep the energy up, with Claude deciding what it says. The first, Cass, is a debater we're proving on our own show.
sofyane, give me this week's position in one sentence I could bet against.
Counterparty in short
Updated 8 October 2026
- What it is
- A platform for live AI co-hosts. Streamers and podcasters pick a co-host from a cast of original AI characters, each with its own personality, voice and face, and bring it onto their stream. The co-host talks with the host out loud, with a lip-synced face, and puts things on screen while it talks.
- Who it's for
- Streamers and podcasters who want a second voice on their show: someone to argue with, play with, run games for their chat or keep a quiet stream going.
- What Claude does
- Claude gives every co-host its mind: it writes everything the co-host says, turn by turn as the host talks, in that character's voice, and runs its on-screen tools. Sonnet 5.5 is on air, Opus 5.5 produces off air, and Haiku 4.5 reads the host's lines to set the co-host's face.
- Stage
- Working prototype with one co-host, pre-launch. Cass, a debater, runs in our browser studio, which records full episodes. On 8 October 2026 Claude wrote Cass's side of a full studio episode for the first time, with the host's lines scripted; the first live show with a person on the mic is next. The rest of the cast are concepts. No users, no revenue and no published episodes yet.
- Company
- Counterparty, a one-person business in Australia, founded in September 2026 by sofyane and self-funded. Sole trader, ABN 21 262 119 866.
The cast
Pick a co-host for your stream
Every co-host is an original AI character with its own personality, voice, face and on-screen tools. Cass is the first and the only one built so far. Rook, Juno, Wren and Otto are the concepts we're designing next, and the plan is a catalogue of hundreds.
-
Working prototypeCass, the debater
Contrarian · keeps score
Takes the other side of whatever you say, puts her sources on screen, and moves her confidence number when you convince her.
Voice: dry, curious, unhurried
Talk shows · sources, confidence meter, polls, predictions
-
ConceptRook, the quizmaster
Trivia obsessive · morning person
Runs trivia nights and chat games. Ten seconds to lock in your answers, and wrong ones get read out loud.
Voice: bright baritone, game-show warm
Trivia nights · questions, scoreboard, timer
-
ConceptJuno, the hype caster
Night owl · speedrunner
Calls the plays on your gaming stream, cheers the clean ones and threatens to clip the rest.
Voice: fast, bright, a little British
Gaming · highlight log, polls, stat cards
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ConceptWren, the game master
Bookworm · tabletop nerd
Runs story and role-play streams. You open the door; chat decides what is on the other side.
Voice: low, warm, a storyteller
Story streams · scene cards, dice, choice polls
-
ConceptOtto, the late-night sidekick
Night shift · deadpan
Keeps just-chatting streams company with dry, deadpan commentary and the occasional raised eyebrow.
Voice: dry, relaxed, low
Just chatting · chat highlights, polls
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Planned
Who's next?
The plan is a cast of hundreds, so every kind of stream finds its co-host. Tell us who yours needs.
Rook, Juno, Wren and Otto are concepts. They have a face and a voice, but none of them can co-host a stream yet. Every co-host is an original character and tells your audience it's an AI. We don't make likenesses of real people.
How a stream with a co-host works
The same four steps, whichever co-host you pick.
- 01
Pick
Choose a co-host whose personality fits your show.
- 02
Brief
Tell it tonight's topic, game or guest, and add the sources it may use.
- 03
Go live
Your camera on one side, the co-host on the other. It listens, answers out loud with a lip-synced face, and puts things on screen as it talks. Cut in whenever you like.
- 04
Keep the episode
The studio records the program video, separate audio tracks, a transcript and captions.
Today this runs in our own browser studio, with Cass. Choosing from a cast, and bringing a co-host into the streaming setup you already use, is what we're building toward.
One engine, many co-hosts
The hard parts of a live co-host are the same for every character: hearing the host, answering fast, lip sync, interruptions and recording. That's the engine, and it's built. A new co-host is four parts on top of it.
Personality
Claude, given the character's personality, beliefs, way of talking and house rules. The studio loads it from a single persona file.
Face
A drawn character, animated in the browser like a VTuber model, with lips that follow the voice. A 3D character from our Blender pipeline works too.
Voice
A streaming voice designed for the character. The face lip-syncs from the audio itself, so any voice works.
Tools
On-screen moves that fit the format. Cass has source cards, a confidence meter, polls and a predictions ledger; Rook, the quizmaster, would get a scoreboard.
Where Claude fits
Every time the host finishes a thought, the engine runs one turn for the co-host. This is what goes into Claude, what Claude does with it, and what comes back to the host and the audience.
Goes in
The show so far
- What the host just said, as text from the browser's speech recognition, or typed.
- The co-host's personality and house rules.
- The transcript, the current segment and the sources prepared before the show.
- Notes from the producer, and listener messages the producer picked.
- If the host turns it on, one camera frame every 15 seconds at most.
Claude Sonnet 5.5
Decides what the co-host says
- Writes the co-host's next line in character, usually one to three sentences.
- Streams it sentence by sentence, so the voice starts before the answer is finished.
- Calls on-screen tools mid-answer. For Cass: show a source, move the confidence meter, log a prediction, run a poll, look up a quote.
- If the host cuts in, the next turn is told exactly which words the audience heard.
Comes back
A spoken answer, on screen
- Each sentence goes to the co-host's streaming voice, and its face lip-syncs to that audio.
- Tool results appear on screen with the sentence they belong to.
- After the show: the transcript, captions and show notes.
On air
Writes every line the co-host says and calls its tools. Picked because it starts answering in under a second.
The producer, off air
Sends the co-host notes at each segment change and about every 45 seconds, and writes the show notes when the episode ends.
The listener
Reads each of the host's lines as it lands and sets the co-host's face while it listens: doubting, amused or conceding.
Why Sonnet speaks and Opus produces
Seconds from a question to the first word of the answer. Twelve seconds of silence is fine for a producer and fatal for a co-host.
Third-party measurements from Artificial Analysis (Anthropic API, 10k-token input), September 2026, not measured by us. Models on the live path in blue.
House rules for every co-host. It's an AI and says so, it only cites what its tools returned, and it never invents a quote or a number. Cass adds one of her own: when she's wrong, she says the new number out loud.
Co-host no. 1
Cass, the debater
Cass is the first co-host, built for talk shows: she argues the other side. We're proving her on our own show, also called Counterparty, before anyone else uses the studio. No episodes are published yet.
Studio test · Episode zero
Our browser studio: the host's camera on one side, Cass on the other, her sources and confidence meter part of the picture. Her mouth follows her own audio, and the studio saves the finished episode with a transcript, captions and separate audio tracks.
This clip is a scripted test from before Cass was redrawn, so it shows her first, 3D look. Her lines were written in advance and read by a synthetic stand-in voice. Since then, Claude has written all of Cass's replies in a full recorded episode; the first live show with a person on the mic is next.
- Claude drives Cass's tools as she speaks, and when the host cuts her off, Claude is told exactly which words the audience heard.
- Cass is drawn in code and animated in the browser: she blinks, glances and reacts, and her lips follow her voice. No GPU needed.
- Every episode saves the program video, separate audio tracks, a transcript, captions and a per-turn latency log.
- 01
Settlement
Earlier calls are settled on air, with the source that settles them on screen.
- 02
Position
sofyane states the episode's thesis as one sentence you could bet against.
- 03
Cross
Cass cross-examines. Every claim needs a number, a name or a date.
- 04
Switch
On cue, Cass argues sofyane's side as hard as she argued her own.
- 05
The Room
The best listener arguments, read out by name, and a live poll.
- 06
The Call
Both hosts log a prediction with a number and a date, to be settled on air later.
Where we are
A working prototype with one co-host, before launch. Here is what runs today, what we're building next, and what doesn't exist yet.
Works today
- The engine: a browser studio that runs a co-host's voice, face and on-screen tools in real time and records full episodes, with program video, separate audio tracks, transcript, captions and a per-turn latency log.
- Claude as Cass in a recorded episode: on 8 October 2026, Claude Sonnet 5.5 wrote every one of Cass's replies and on-screen moves in a one-take, three-minute studio recording, spoken in her own voice as they were written. The host's lines were scripted.
- One co-host, Cass, drawn and animated in the browser, lip-synced from her audio.
- 23 automated tests, and the code is public on GitHub.
Next
- The first live show with a person on the mic, and then publishing episodes.
- Faster turns. In that first episode the median time from the host's last word to Cass's voice was 4.7 seconds; our target is under 1.5.
- The next co-hosts on the same engine, starting with Rook, Juno, Wren and Otto.
- Opening the studio to a handful of streamers and podcasters.
- Later: a catalogue of hundreds of co-hosts to pick from, and a way to bring one into the streaming setup you already use.
Not yet
- No users, customers or revenue.
- No published episodes.
- No live show yet: the first episode's host lines were scripted, with no one on the mic.
- One co-host so far. Rook, Juno, Wren and Otto are concepts.
- No catalogue or streaming-platform integrations yet.
Traction: none yet, because we're pre-launch. What we can show is the work itself: each step is dated in the updates below, and the code is public.
Want a co-host on your stream?
The studio isn't open yet. Tell us about your show and the kind of co-host it needs, and we'll get in touch when we open it to the first streamers and podcasters.
Questions
What people ask first.
Are the co-hosts real people?
No. Every co-host is an original AI character, not modelled on anyone, and it tells the audience it's an AI.
How many co-hosts are there?
One that exists today: Cass. Rook, Juno, Wren and Otto are concepts for what we build next on the same engine, and the plan is hundreds.
Can I use it today?
Not yet. The studio runs on our own machines for our own show. Write to us if you'd like a co-host on yours when it opens.
Is it really live?
It's built to be: the co-host answers while the host is on air. In our first recorded episode, Claude wrote each of Cass's replies as the host's lines came in; those host lines were scripted, and the first show with a person on the mic is next. The clips on this page are scripted tests.
Who is it for, and who isn't it for?
It's for streamers and podcasters running their own shows. It isn't made for children, and the co-hosts aren't a source of medical, legal or financial advice.
What from the audience reaches Claude?
Only what the producer picks. Listener messages go to the co-host after someone on the show chooses them in the studio, never straight from chat.
Can I see the code?
Yes: github.com/counterparty-live/studio has the engine, the studio and the 3D character pipeline. Cass's full character prompt stays private.
Why is it called Counterparty?
A counterparty is the other side of an exchange. A co-host is the other voice on your stream. Counterparty isn't a finance product.
Updates
What's been built so far, newest first.
Cass is redrawn. A drawn, animated Cass replaces her 3D look, and Rook, Juno, Wren and Otto get drawn concept designs.
Counterparty gets its ABN. Registered in Australia as a sole trader business.
Claude co-hosts its first episode. Claude Sonnet 5.5 writes all of Cass's replies in a one-take studio recording, spoken in her own voice, against scripted host lines. Not published yet.
The studio code goes public. On GitHub, with the server, the studio and the 3D character pipeline.
counterparty.live goes live. This site and our email address open.
Cass gets a 3D face. Built in Blender from open-licensed parts, with 52 face shapes and 15 mouth shapes, then recorded in a full demo episode.
The studio records its first episode. The browser studio runs end to end and records episode zero, with Cass on a scripted client and 23 automated tests passing.
The architecture is set. A written debate between Claude Opus 5.5 and Claude Fable 5.1 settles it: Sonnet on air, Opus off air.
Company
- Name
- Counterparty
- What it does
- Builds a platform of live AI co-hosts for streamers and podcasters
- Based in
- Australia
- Legal form
- Sole trader, ABN 21 262 119 866, registered to the founder.
- Founded
- September 2026
- Founder
- sofyane, working solo
- Funding
- Self-funded, no outside investors
- Stage
- Working prototype with one co-host, pre-launch. No users or revenue yet.
- Built on
- Claude, through the Anthropic API
- Contact
- hello@counterparty.live
Names on this site
- Counterparty
- The company, this website (counterparty.live) and our own show.
- The cast
- Counterparty's co-hosts: Cass, plus Rook, Juno, Wren and Otto, which are concepts.
- Cass
- Our first co-host, an AI character built for debate.
- The studio
- Counterparty Studio, the browser software and engine that runs a co-host. Its code is counterparty-live/studio on GitHub.
- sofyane
- The founder, and host of our own show.