Kurzz -- Jazz Ensemble Simulation

Kurzz is a jazz ensemble simulation. You connect as a player alongside two AI musicians and contribute to a live musical form that the simulation generates in real time. There are no tracks, no samples, and no pre-recorded loops -- the audio is synthesized fresh on each step of the simulation clock.

It is not a music game. There is no score, no win condition, no correct answer to what note to play. What there is: a repeating musical structure, three musicians who are actually running in the simulation and responding to each other, and a set of signals (cam, VM, tension) that describe what is happening in the ensemble. You observe those signals, take a role, and play.

The rest of this guide covers who you will be playing with, what the roles mean, how to start your first session, and how to read what the simulation is telling you.

If you have not connected to a Kurzz server yet, start with Getting Started. If you want background on parties, activities, quests, and ren scenes, read Parties and Activities first -- it explains the scaffolding that Kurzz sits on top of.

The characters

Velda and Kepler are in the party before you get there. They are not placeholder NPCs filling seats; they are entities in the simulation with state, responses to ensemble pressure, and opinions. The ren scenes they trigger when you hit milestones are not congratulatory pop-ups -- they are responses to what your party actually did.

Velda

Velda is the bassist. Her default jazz role is anchor: she holds the rhythmic and tonal ground, plays economically, and does not fill space she does not need to fill. She has been doing this a long time.

When you complete the First Note quest, she appears:

"You played something. Good. The ensemble noticed." "Don't wait for permission. This band answers forward motion."

When you complete the First Form quest -- meaning you were present for a complete cycle of the 12-bar form:

"Full cycle. The form closed and you were inside it." "Most people don't notice when that happens. You did."

Her tone is direct. She is not being hard on you; she is treating you like a musician.

Kepler

Kepler plays keys. His default role is support: he fills around the lead, reinforces the harmonic structure, and pays attention to the overall shape of what the ensemble is building. He is technically minded -- he thinks in patterns and tracks what the simulation is signaling.

When you take the Lead role for the first time, he appears:

"You took the Lead. Watch the cam. When it climbs, your cost goes up." "The ensemble follows pressure. You just became the source."

His scenes tend toward the instructional without being dry. He is pointing at things worth watching.

Jazz roles

Each musician in the ensemble holds one of four roles at any given time. Your role determines your position in the musical hierarchy -- who the ensemble is following, who is filling, and who is holding the ground.

Anchor -- holds rhythmic and tonal stability. The anchor is not passive: holding ground under a lead that is pushing the cam is real work. It is the role with the lowest cost and the highest stability. Velda starts here.

Support -- fills around the lead, reinforces the structure without claiming it. A good support player makes the lead sound better. Kepler starts here.

Lead -- carries the musical statement. The ensemble follows the lead's pressure. When you hold this role, the cam (collective attention metric) responds to what you play. If it climbs, your cost of holding the position increases. You are the source of musical pressure for as long as you stay in the lead.

Soloist -- takes a featured turn. The most exposed position in the ensemble. The rest of the musicians orient around the solo.

Roles are not locked. You can shift roles during a session and the simulation responds to who holds what in real time. You do not need to stay in one role for a whole form cycle, though the quest arc will encourage you to hold each role at least once so you can feel the difference.

The role panel in the session UI is where you make these changes. (The exact controls are being developed alongside the panels; the GraphQL Console is a fallback if the panel is not yet live in the version you are running.)

Your first session

Here is the full path from "just connected" to your first ren scene. You should have a Kurzz runner live at port 7321 (or wherever your setup person told you it is running).

Step 1: Connect to the runner. Open the Server Browser and add or click on the Kurzz server. When the connection strip reads "Connected" and the realm shows "kurzz", you are in. See Getting Started if the connection is not working.

Step 2: Open the Party panel. The Party panel opens automatically after a successful connection. You will see any parties that already exist on this server. In a fresh Kurzz instance there may be none, or there may be a party left over from a previous session.

Step 3: Create or join a party. If no party exists, click Create Party, give it a name, and confirm. If a party is already there and you want to join it, click Join next to it.

Once you are in a party, Velda and Kepler will be listed as AI members. They are already there.

Step 4: Start a jazz activity. From inside the party view, find the "Start Activity" control and choose kind jazz. When prompted for a venue, select Blues Anchor Session -- this is the 12-bar blues form and is the right starting point. Confirm to start.

Step 5: Wait for the session panels to populate. As soon as the activity starts, the simulation begins generating audio and the panels come live:

The Timeline panel shows the form position -- which bar you are on and how far you are from the end of the current 12-bar cycle.
The Jazz Cue panel shows guidance signals and tutorial cues from the simulation as the session runs.
The Party/Roster shows who is in the session and what role each musician holds.

If audio does not start immediately, see Common Questions below.

Step 6: Play a note. Use the note input in the session UI to play a single note. Do not overthink it -- the First Note quest requires exactly one note.

Step 7: Watch for Velda. After the quest completes, a ren scene fires. Velda appears and speaks. Depending on where the VN panel is in development, this may appear as a full dialogue sequence or as a notification. Either way, the content is real and the trigger was live.

From here, keep playing. The next milestone is First Form -- completing one full 12-bar cycle -- and then First Lead, which is where Kepler's scene fires.

The quest arc

These quests proceed roughly in the order listed. The simulation assigns several of the early ones concurrently, so you will see them in parallel. You do not need to pursue them; they complete as you participate.

Quest	How to complete	Ren scene?
First Note	Play one note in a session	Yes -- Velda
Phrase Burst	Play five notes in a session (repeatable)	No
First Form	Be present when the 12-bar form completes one full cycle	Yes -- Velda
First Lead	Hold the Lead role at least once during a session	Yes -- Kepler
Soloist's Turn	Hold the Soloist role at least once	No
Anchor Session	Hold the Anchor role at least once	No
Role Explorer	Hold Lead, Support, and Anchor at least once each	No
Scene Stealer	Complete a gig in a room that already has rumor heat	No
Form Chain	Complete multiple consecutive form cycles	No
Rumor Starter	Establish rumor heat for a room through musical presence	No

Phrase Burst is repeatable and designed to fire multiple times in a single session. The rest are one-time milestones.

Role Explorer requires completing at least First Lead and Anchor Session first -- you will not see it assigned until those are done.

The later quests (Scene Stealer, Rumor Starter) connect the musical dimension to the venue heat system, which tracks cumulative activity at specific physical locations in the scenario. They are a different kind of question: not "did you play" but "did your presence leave a mark."

Point values for each quest are defined in the scenario spec and are visible in the quest panel when a quest is active or completed. Early quests carry lower values; Role Explorer and Scene Stealer are worth more, which roughly reflects how much the simulation had to track before they could fire.

Listening to the simulation

While a session is running, two signals are worth watching: the cam and VM readings visible in the timeline or roster panels.

cam (collective attention metric) measures musical pressure and tension across the ensemble. It rises when the lead is pushing hard, when the form is heading somewhere, when musicians are responding to each other. It falls when things settle. The cam is not a score -- it does not have a "good" direction. High cam means the ensemble is in a state of elevated engagement and elevated cost. Low cam means it has relaxed.

What the cam affects directly: when you are in the Lead role, your cost of holding that position is tied to the cam level. A high cam and a Lead role is a demanding position. When Kepler says "when it climbs, your cost goes up," he means this literally -- it is a simulation value, not a metaphor.

VM (vitality margin) is a per-musician signal of engagement and energy. Each member of the ensemble has a VM value. High VM means they are present and active. Low VM means they are fading -- playing less, contributing less, holding back.

VM is not something you set directly. It is an output of the simulation's internal dynamics: how the ensemble is functioning, how much pressure is in the system, how the form is progressing. You can influence it indirectly through what you play and what role you hold, but you cannot control it.

Why the music changes: The synthesis is driven by these signals in real time. When the cam rises, the ensemble shifts -- musicians adjust their density, timbre, and register. When a musician's VM drops, you may hear them pull back. When the form closes and begins again, there is a structural reset that the musicians respond to. What you are hearing is the simulation state expressed as audio, not a triggered clip.

This is what makes Kurzz different from a music application with playback. There is no backing track. The music is a real-time projection of what the simulation is doing.

Common questions

I played a note but nothing happened. Notes take a moment to be processed by the simulation and reflected in the quest system. The Timeline panel is the most direct indicator of what the simulation has received. If the note appears in the timeline but the quest has not updated, wait a few seconds -- quest evaluation runs on the simulation clock. If nothing appears in the timeline at all, the activity may not be running; check the Party panel to confirm there is an active jazz session.

I cannot hear any audio. Audio output requires the runner to be compiled with audio support enabled. Not all runner builds include it -- this depends on your setup. Ask whoever configured your runner whether audio is enabled. If you are running the runner yourself, check the Plantangenet build documentation for the audio feature flag. The simulation runs and all other panels work correctly without audio; you are only missing the synthesis output.

How do I switch my role? Role switching is done through the role controls in the session UI. The exact panel for this is actively being developed; the controls should be visible inside the party or roster view during an active jazz session. If they are not yet available in the version you are running, you can issue a role change via the GraphQL Console using a mutation.

What is "the form"? The form is the repeating musical structure that the session runs on. In the Blues Anchor Session, it is a 12-bar blues cycle. The simulation counts through all 12 bars, then starts again. This cycle is continuous -- it does not stop between repetitions. The Timeline panel shows your current position within the form: which bar you are on and how close the end of the cycle is.

Most jazz forms are repeating structures like this. The form gives the ensemble a shared framework: everyone knows where the cycle is, and musical decisions are made relative to that position. Your First Form quest completes the first time the cycle closes with you inside it.

Do the AI musicians respond to what I play? Yes, within the bounds of what the simulation tracks. The simulation observes ensemble state -- cam, VM, role distribution, form position -- and the AI musicians' behavior is driven by those signals. If you take the Lead role and push the cam up, the ensemble responds to that. If you pull back, they respond to that too. The response is not note-for-note imitation; it is behavioral, driven by the same dynamics that govern everything else in the simulation.

Parties and activities background: Parties and Activities Connection and setup: Getting Started Inspect server state directly: GraphQL Console