chore(memory): LRN-073/074 + EVAL-010 — prune-memory chantier close

- LRN-073 — a skill's worked-example must use FICTIONAL ids, never live registry
  ids (they prime real-data behavior). The RED-7 root-cause lesson.
- LRN-074 — system grep/awk may be ugrep/mawk: don't assume flag-parsing, use
  /usr/bin/grep, watch the RED go red. 4th command-assumption miss this session →
  engraved as a recurring pattern-family (alongside fail-silent LRN-066/071).
- EVAL-010 — prune-memory hardening: RED-7 deterministic fix + RED-8 accept +
  34-row backfill; anomalies incl the real-time false-green catch and the near-
  collision with the existing EVAL-009 (caught by reading first).
- journal 2026-06-29 (cont. 3) + TODO chantier section; BLK-011 finish/push marked.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01C6bUdvHnajCNzgVQefZowj

.claude/memory/learnings.md

@@ -92,6 +92,8 @@ rules:
 | LRN-070 | 2026-06-29 | clean-tree-gated migration blocked by a dirty submodule → diagnose pointer-vs-content; for a local edit use `submodule.<name>.ignore=dirty`, never blind reset | migrating/releasing a superproject whose submodule carries intentional local edits |
 | LRN-071 | 2026-06-29 | fail-loud must cover the helper's OWN commit, not just its inputs — 3rd occurrence of the swallowed-commit pattern (a failed op masked by a later returning-0 statement) | any helper whose return value gates a downstream "success" — audit every fallible internal op propagates, esp. the commit |
 | LRN-072 | 2026-06-29 | a stranded-artifact bug can be fixed by NOT creating the artifact (negative diff), not by plumbing its commit — if the producing step is speculative/unused, delete it | a stranded/duplicated/uncommitted-artifact bug — before building machinery, ask if the PRODUCING step is wanted; speculative-at-creation → remove, deliberate-on-demand → keep |
+| LRN-073 | 2026-06-29 | a skill's worked-example must use FICTIONAL ids, never live registry ids (they prime real-data behavior) | any skill/agent with a worked example over the SAME data it operates on — use reserved/fictional ids; test deterministically that no live id appears |
+| LRN-074 | 2026-06-29 | system `grep`/`awk` may be ugrep/mawk: don't assume flag-parsing, use `/usr/bin/grep`, watch the RED go red (4th command-assumption miss this session) | any shell test/guard riding on grep/awk/sed semantics — pin `/usr/bin/<tool>`, run the assertion, confirm it reds on the defect before trusting green |
 
 ---
 
@@ -828,3 +830,13 @@ rules:
 - **pattern**: 3rd member of the post-FINISH-artifact class (memory, docs, GSD ROADMAP) — but UNLIKE the first two (real artifacts ALWAYS produced → couple a commit), the GSD artifact came from a SPECULATIVE, opt-in, rarely-used producer (init-project auto-bootstrapping a multi-session engine at project creation). The reflex fix (reorder + build `gsd-commit.sh` + tests) would have added machinery to faithfully commit an artifact nobody uses. The right fix was a NEGATIVE diff: delete the producer → orphan never created → bug dissolves, zero new code (BLK-011).
 - **the refutation that got there**: the framing "ROADMAP redundant with TODO" was WRONG (gsd ≫ roadmap = state machine/crash-recovery/cost/parallel/worktree; TODO ≠ gsd ROADMAP = different altitude + consumer). Reading REFUTED both premises, yet the CONCLUSION (remove the step) held for a STRONGER reason: speculatively scaffolding a heavy engine the sole user doesn't use, at creation, is bad per se. Right answer, reason corrected before engraving — change the QUESTION before changing the code.
 - **future application**: a stranded / duplicated / uncommitted-artifact bug → BEFORE building machinery to handle the artifact, ask whether the step that PRODUCES it is actually used / wanted / non-speculative. Speculative or unused (esp. a personal/single-user repo) → DELETE the producer; the cleanest fix is the absent one. Distinguish speculative-at-creation (REMOVE) from deliberate-on-demand (KEEP). Family: [[BLK-010]], [[BLK-011]], [[BDR-036]].
+
+## LRN-073 — a skill's worked-example must use FICTIONAL ids, never live registry ids (they prime real-data behavior)
+- **pattern**: prune-memory's STEP-2 plan example named real LRN-014 + LRN-016 ("merge these"). A real-data run merged exactly that pair — though they're COMPLEMENTARY (header-ids vs checkbox-CSS), a merge its own rule forbids. Example ids that match live entries, in context at audit time, PRIME the action: you can't tell "judged correctly" from "pattern-matched its own example".
+- **fix**: fictionalize example ids (9xx — can't match a live registry) + make the example model a CORRECT action. Lock it DETERMINISTICALLY ([[LRN-046]]): assert the example carries only fictional ids — not a flaky behavioral "did priming fire" test (RED-7).
+- **future application**: any skill/agent whose instructions contain a worked example over the SAME data it operates on (registries/files/records) → use reserved/fictional identifiers; test deterministically that no live id appears in the example block.
+
+## LRN-074 — system `grep`/`awk` may be ugrep/mawk: don't assume flag-parsing, use `/usr/bin/grep`, watch the RED go red
+- **pattern**: a RED-7 test used `grep -vE '-9[0-9][0-9]$'`; the system grep is UGREP → parsed the leading `-9..` as an OPTION → errored → empty → FALSE GREEN (a RED that never goes red). Caught only because the output was READ, not assumed. 4th time this session an assumed command behavior was false on execution (after `set -o pipefail` + `grep -q` SIGPIPE, …). The skill's own verify already hard-codes `/usr/bin/grep` (line 189) for this exact reason — re-learned.
+- **fix**: `/usr/bin/grep` (GNU) where GNU semantics matter; avoid leading-dash regex args (or use `-e`/`--`); never trust the system tool is GNU/POSIX (mawk≠gawk, ugrep≠grep).
+- **future application**: any shell test/guard whose correctness rides on grep/awk/sed semantics → pin `/usr/bin/<tool>` AND run the assertion, confirming it goes red on the defect before trusting green. Execute, don't assume command behavior. RECURRENT motif — audit any "assumed tool behavior" the way the fail-silent family ([[LRN-066]]/[[LRN-071]]) is audited.