Genesis · 5,678 cats · free mint
A cat is a song first. The portrait is that song, drawn in light.
A BassGPT-derived engine writes each cat's line over a jazz form. Every note's colour is its frequency, folded into visible light.
Pre-mint page. Images on this page are practice-seed previews, not the launch cats.
01 / What
What are JazzCats?
5,678 generative jazz-cat musicians. Cats, big cats, alien cats, humans and signal ghosts. Each one is born with an instrument, a key, a form, a tempo and a number of choruses, and the song follows from that.
The mint is free. You pay only gas. The art is not on a server and not on IPFS: each cat's art is published on-chain at reveal, from bytes committed at deploy. The contract has no function that changes a cat's art or traits after that, for the owner or anyone else.
- cats
- 5,678
- mint price
- 0 + gas
- art + traits per cat, on-chain
- about KB
- edits to art after deploy
- none
02 / The signal portrait
Each note's colour is a calculation.
A portrait is made of glyphs: ASCII, RTTY teleprinter and ABC-notation marks. The colours are not decoration. Each note the cat plays is a colour.
The note's frequency in Hz is folded by octaves into the visible spectrum, 380 to 760 nm, then mapped to a colour with the CIE 1931 colorimetric data. Tap a note and check the arithmetic. Below, the same calculation runs on the real songs.
Checked against real cats
In the 5,678-cat practice build, 0 cats have an eye colour that names a note. For every one of them, the colour computed above is present in that cat's own art. Three of them, below.
/\_/\ ( o.o ) > ^ <RYRYRYRY CR LF.:=-+*#%@K:Am |: A2 cB A2 :|Special inks, as drawn in the practice build: Monotone Teleprinter (RTTY) , Resonance , Scoreline (ABC notation) of 5,678. The rest are Spectral, where each cell has its note's colour; a Monotone cat prints in one ink. The frequency-to-colour step is a display mapping, not a physical sound-to-light conversion. CIE 1931 data: International Commission on Illumination, DOI 10.25039/CIE.DS.xvudnb9b, CC BY-SA 4.0, 380 to 760 nm excerpt, linearly interpolated.
03 / The song
The engine writes the line. The portrait draws it.
Each cat's song is written by a BassGPT-derived engine over a jazz form. Every cell of the portrait picks one note of that song and takes that note's colour.
The bass plays a walking line in quarter notes. Sax, trumpet, guitar and piano play eighth-note lines chosen the same way. Drums, and the chords that guitar and piano comp, come from a companion engine, MJI. The sound is original synthesis: no recordings and no sample packs.
The song is not stored on-chain. The art is. The pinned engine regenerates the song from the cat's birth recipe, and you can do that here.
- Birth recipeengine cat number, instrument, key, form, BPM, choruses
- Engine writes the takea line over the form, bar by bar
- Each note gets a colourHz, folded into 380 to 760 nm
- The portrait is drawnevery cell points at one note
Hear a cat and watch it play
These are practice-seed cats, built the same way as the launch cats. Press play: the cells of the sounding note light up, and the readout names the note, its frequency and its colour.
Sound starts only when you press the button, and nothing is uploaded. Guitar and piano play their real chord voicings.
Voices, by planned scarcity
Instrument is which voice plays the line. These are the planned draw weights out of 5,678; the realised counts in any build vary a few percent.
- common
- guitar · bass · piano
- uncommon
- sax
- rare
- trumpet
- rarest
- drums
04 / Rarity
What is in the set.
Species
Exact counts, summed over roles: musician 5,000, club owner 500, booker/label 178.
Inks
Special inks are approximate here; the rest are Spectral.
Instruments
Planned draw weights, with the count each drew in the practice build. The launch draw differs by a few percent.
Practice-seed gallery
Labelled practice-seed preview: real portraits from the production engine and renderer, practice seeds, not the launch. Tap a cat for its traits and its check.
05 / Mint and reveal
Three steps.
- Mint free.Pay only gas. Every cat shows a sealed card until reveal. Nothing about a cat can be read from the contract yet.
- Sell-out arms the shuffle.After the 5,678th mint, or when the owner closes the mint early, the contract arms a shuffle for 10,800 blocks later, about 36 hours at 12-second blocks. It will use the hash of that block, which nobody can know at mint time.
- Reveal, 1 to 2 days later.Once that block has passed, anyone can call the shuffle. Then each cat's art is published on-chain, one cat at a time, and only bytes that prove into the committed root are accepted.
The chain at launch is not final. This page does not state one.
Early allowlist window
Holders of these collections get an early window. The rest is public supply.
06 / On-chain proof
What is on-chain, and what is regenerated.
The art is on-chain. The song is written again, by the pinned engine, from the birth recipe.
On-chain: each cat's art and its traits (instrument, key, form, BPM, choruses, species, ink, and the rest) are stored in the contract after reveal and drawn into an SVG on request. After the shuffle, the birth recipe itself is readable from the contract.
Off-chain, regenerated: the notes you hear. The engine release is pinned by a hash recorded in the birth policy, so the same recipe gives the same song and the same picture.
One Merkle root, set at deploy, commits all 5,678 cats. Each leaf binds the slot, the birth recipe, the payload length and the hash of the exact compressed bytes. At reveal the contract accepts a cat's bytes only if they prove into the root. No one can swap a cat, and the contract has no function to change one afterwards. The owner can change only where each cat's agent endpoint answers.
- Merkle root
- Published at deploy. None is shown here: these are practice seeds, and the launch seeds are not public.
- Art + traits per cat
- about KB on average, KB at most, compressed (measured over the 5,678-cat practice build)
- Storage
- On-chain, in the contract. No server, no IPFS pin.
- Song and art check
- of gallery cats checked passed; dropped. For each: the portrait rebuilt from the song is byte-identical to the art in its payload, its traits equal the recipe, and painted cells each carry their note's frequency. The check is
scripts/premint-gallery.mjsin the repo; a standalone public verifier is not published yet.
07 / The agent layer
A cat an AI can read.
Each token carries 721T-style agent metadata and an A2A agent endpoint record.
That lets AI agents such as Claude or Codex read a cat, and later play through it in the New Jazz City game world. The record holds no spending authority. The game world is the longer-term layer; it is not part of the mint and nothing here promises when it ships.
contextendpoint[a2a]jazzcats.genesisjazzcats.musicjazzcats.artifact
The five contract metadata keys above are what an agent reads.
08 / FAQ
Short answers.
What does it cost?
The mint is free. You pay only the network gas for your transaction. Revealing a cat later also costs gas, paid by whoever publishes it.
Can the art change?
No. One Merkle root, fixed at deploy, commits every cat. The contract only accepts bytes that match it, accepts each cat once, and has no function to replace the art or the traits.
When is the reveal?
After the 5,678th mint (or an early close by the owner) the contract arms a shuffle for 10,800 blocks later, about 36 hours. After that anyone can finalize it, and then each cat's art is published on-chain. Plan for one to two days.
Can anyone predict which cat they get?
Not at mint. Which art lands on which token is set after mint-out by the hash of a block that does not exist yet when you mint.
Which chain?
Not final. This page says only "the chain at launch".
Where does the music come from?
A BassGPT-derived engine writes each cat's line over a jazz form, from the cat's birth recipe. Drums and comping come from a companion engine, MJI, and the sound is original synthesis with no recordings. The song is not stored on-chain; the pinned engine regenerates it, and the portrait is its picture.
Do the images here show launch cats?
No. They are practice-seed previews made by the same engine and renderer. This page publishes no launch seed and nothing that predicts a launch cat.
Does a cat give spending power to an agent?
No. The agent record carries no spending authority.
Is this financial advice?
No. Nothing here is a promise of price, return or utility. Read the contract.
09 / About
Who built it.
Kyle Benford is a jazz drummer. He studied at Juilliard and was mentored by Wynton Marsalis.
He played New York bandstands from 2017 to 2022, including Smalls and Mezzrow. He recorded on Micah Thomas's Tide and on Giveton Gelin's True Design (with Immanuel Wilkins) and Island Dreamer (featuring Jon Batiste).
He built BassGPT, the engine that writes these songs. His great-uncle, Tommy Benford, was a jazz drummer who played with Jelly Roll Morton and Django Reinhardt.
10 / Work
The record, in public.
Writing and music from the Department of Jazz. Every link opens the original post.