Journal · 7 August 2026
A first devnet exercise that still belongs on paper
The library’s first cluster exercise asks for a signature and a before-and-after account, written out, before anyone discusses a program.
Why the exercise is small
Devnet is where readers want to feel busy. The library exercise refuses that. You create or reuse an account on devnet, record the lamports and data length, send one simple transfer or allocation that the shelf has already named, and record the same fields again. Then you write the signature on the exercise sheet.
We ask for the signature because “it worked” is not a note we can review. A signature lets the next sitting look at the same transaction without trusting the memory of the afternoon.
What we keep off the sheet
The sheet has no field for a seed phrase and no field for a private key. If a reader arrives with either written down, we stop and ask them to put that paper away before the exercise continues. Public addresses and signatures are the whole of the evidence.
Cluster names go on the sheet because a mainnet signature and a devnet signature answer different questions. The first exercise is devnet only. Mainnet shows up, if ever, in a later path when the reader can already explain the fee they are about to pay.
Bring it to a review, not to the circle
This exercise is a path or checkpoint item. The Thursday circle will not debug a failed signature in front of six people. If the before-and-after lines do not match the signature, book a desk hour and bring the sheet. Junho would rather spend the hour on one mismatched field than on a tour of the cluster.
When the lines match, file the sheet in the booklet. That page becomes the proof that week’s shelf was touched, which is all the path needs from a cluster.