The whole thing, in plain language
TSUNAGI is an independent Cardano block-producing node, written from scratch in Zig. It is not a fork of the existing node, not a wrapper around it, and not a simulation. It has produced real canonical blocks on the Cardano Preview network, which anyone can verify on-chain. This page explains the five parts that make it up — without jargon, and without selling anything.
A Cardano block producer has one core job: when the protocol picks your pool to make
the next block, build that block, sign it, and get it to the network before the slot
passes. TSUNAGI does exactly that. For every slot it checks whether it has been elected
(a private lottery based on stake), and if so it forges the block, signs it with the
pool's keys, and serves it to ordinary cardano-node peers over the standard
protocols. They accept it into the chain under the normal consensus rules — competing
against every other pool's blocks. Nothing is special-cased for TSUNAGI.
A block producer that crashes at the wrong moment misses its slot, and the block is gone. The Guardian is a small supervisor that watches the node, and if the node dies it restarts it automatically — in seconds, with no human awake. It does not touch the keys, the protocol, or the block logic; it only ensures something is always running. This has been proven in production: the Guardian has detected a killed node and brought it back, after which the recovered node went on forging canonical blocks.
Kintsugi is the Japanese art of repairing broken pottery with gold, so the break becomes part of the object's history rather than something hidden. Here it is the failure-memory system: every real incident is written down — what broke, why, and how it was fixed — and pinned with a regression test so the same fault cannot silently come back. The incident record is public. The point is honesty: TSUNAGI does not pretend it never broke; it shows the breaks and what was learned from each one.
The Cockpit is a plain text console an operator can open to see the live state in one screen: how many blocks, the current streak, the next time the node is due to lead, the Guardian's health, key-rotation timing, and recent events. It only observes — it never controls the node. It is deliberately boring and dependency-free, so the thing you use to check on the producer can never itself become a new way for the producer to break.
It is easy to say a node can do something. A reality proof is the opposite: a capability only counts once it has actually happened — in production, or in a verified rehearsal — with evidence on record. Producing canonical blocks is proven. Recovering a crashed node is proven. Some things are honestly still open: they have not yet occurred, so they are listed as not-yet-proven rather than claimed. The live tally is on the proof page (several proven so far).