Learn it the way it works: every level you pass leaves a record anyone can check.
onetrace is a tool for proving what a pipeline did. So the course is built the same way. Each level is a task with a definite output: a run folder, a comparison, a refusal the verifier names. You pass a level when the verifier says so, on your own machine, with no account; nothing is sent anywhere except at the one timestamp level, which says so. Your progress is a chain of records, and a badge is a signed record you can give to anyone to check.
How it works
Levels, in a chain.
A level gives you a task and tells you exactly what its output must look like. Most levels take the previous level's output as their input, so a track is a chain: skip one and the next won't verify, the same way a record won't verify once a receipt is missing.
Build levels
Record a run, change one setting, sign it, timestamp it, keep an input and erase it again. The output is a run folder that the verifier passes.
Break-it levels
You are asked to make the verifier refuse in a named way: edit a receipt after the run, or pay on a denied decision. You pass when the verifier names exactly what you did. That is how you learn what the record protects.
Detective levels
Two runs on the live demo, a changed answer, and a question: which stage changed first, and what setting changed there? The record is the answer key, and the console's own answer is there to check yourself against afterwards.
The tracks
Two tracks, fourteen levels.
Track 1: record, check, compare
Nine levels on onetrace 0.5.0: eight on your own machine and one on the live demo. Your first verified run; breaking the chain on purpose; two runs and the first difference; a detective level on the live demo; release noise and masking; keeping an input and erasing it; signing; timestamping; reproducing a stage. About two hours, on your own machine.
Track 2: decisions, tracing, nesting
Five levels on what onetrace 0.5.0 added: a step gated by a decision; paying on a deny, and the verifier catching it; a run inside a trace; a step inside a step; and a boss level on the live demo's planted incidents, a payment made on a deny, a permit for another amount, and an agent whose sub-agent's run differs. About an hour; four levels on your own machine, one on the demo.
Badges
A badge is a record, not a picture.
When you pass a level, the proof is the run folder the level produced. A badge is a onetrace run of its own whose inputs are that folder's chain head, signed with your key and timestamped if you choose, which onetrace-verify checks like any run. A track badge is a run whose inputs are the level badges' chain heads: it verifies only if every level does.
Nobody issues it
Your badge is your own record. There is no server, no account and no list you must be on. You can publish the folder, or just its chain head, and anyone with the verifier can check it.
What it says
That records of yours verify and have the shape the level asked for. Nothing about speed, rank or skill. The badge reads "completed", never "correct" and never "expert".
What it holds
Your key id, the level, the checks and their results, and the chain heads it rests on. No name, no email, no path from your machine. A display name is yours to add, as a declared setting.
Today: both tracks' fourteen levels are written and the checks are the verifier's, so you can do all of them now and keep the folders. The onetrace quest command that writes the badge records from those folders ships with a later release; until then your folders are the proof, and they will be the badge's inputs when it lands.
What it is not
No points, no timers, no leaderboard.
They would reward speed and volume, which the record doesn't measure, and they would need a server that keeps scores, which this project doesn't run. A level is passed or not, by the verifier's reading. No level is judged by a model, and no badge is given for a judgment ("explained a run well"), since no record can check one.