2026-10-06 — Built retrieval-coach skill v1 (strict retrieval practice, Google Doc ledger per learning project, never gives the answer). Build decisions: cue ladder cut to three steps (gap type → one narrowing cue → reread) to match "three failures then reread"; Source Map placed last in the ledger under an ANSWER KEY warning because the learner can open the Doc; if the original source is unavailable, a third failure is marked FRAGILE ("reread pending"), not UNDERSTANDING BLOCKED, since forgetting can't be told from not understanding without a reread; selection gate nominates ideas by name only so first free recall isn't contaminated. Open risk: tests were self-simulated by the builder, not run independently; first real session is the true test.