Adaptive planning

Flow budget

The flow budget summarizes how much challenge the next view can carry. Density controls how much eligible content is exposed; minimum gap prevents adjacent replacements from turning a paragraph into a test.

Unit tier

Candidates form a macro ladder:

1. word
2. phrase
3. sentence pattern

The planner promotes larger units only when proficiency and prior encounters support them.

Reader memory

ReadingMemoryRow stores per-concept mastery and friction. ReadingMetricsSample captures signals such as pace and backtracking. These structures remain with the reader application; the core package does not require a particular database or sync service.

const rules = planReplacements(expressions, sessionState, {
  budget: { density: 0.55 }
});