Definition of Done

A course lesson is done when

• its stated product/code outcome exists;
• its completion-gate tests pass;
• you can explain the main concept in simple language;
• relevant current docs match the implementation;
• docs/status/CURRENT.md points at the next lesson;
• no hidden unfinished work is being called complete.

A milestone is done when

• all required lessons are complete;
• the milestone acceptance scenario works manually/deterministically;
• full relevant test suite is green;
• important error paths are visible/actionable;
• Learning Log/open decisions are updated from evidence;
• architecture remains simpler than the problem requires, not more complex.

A substantial AI-generated change is done when

• you reviewed the diff;
• you understand new abstractions/dependencies;
• tests were run;
• agent did not silently broaden scope;
• architecture/docs were updated if behavior changed.

“Works on happy path” is not enough for lifecycle code

For Operations, Git/worktrees, provider Runs, sync, and migrations, Done also includes at least one meaningful failure/restart/edge-case test appropriate to the lesson.