fix(prune-memory): RED-7 fictional example IDs + RED-8 accepted limit

RED-7 (example-priming): the STEP-2 worked example named live IDs (LRN-014 +
LRN-016) and modeled merging them — but they are complementary (header-ids vs
checkbox-CSS), a merge the skill's own rule forbids. Live IDs in an example prime
the skill to act on those exact entries on real data. Fictionalized the whole
STEP-2 example to 9xx IDs (cannot match a live registry); the merge example now
models a same-concept merge. Closed by a DETERMINISTIC test (run-deterministic.sh
RED-7: the example must carry only 9xx ids) per LRN-046, not a flaky behavioral
fixture. The test caught its own ugrep false-green first (a leading-dash pattern
parsed as an option) — fixed via /usr/bin/grep, the same dodge the skill's verify
already uses at line 189.

RED-8 (added-negation inversion): re-reviewed, consciously accepted as a documented
limit in BACKLOG — remote (compression subtracts tokens), and an FP-safe increase
check is non-trivial (needs the HEAD entry-id set to exclude legit new/merged 0->N);
a noisy guard is worse than the honest limit on a destructive skill (LRN-047).

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

skills/prune-memory/SKILL.md

@@ -112,21 +112,23 @@ Print one block per registry. Example:
 
 ```
 PRUNE PLAN — decisions.md (N entries → M after if approved)
+(IDs below are FICTIONAL — 9xx range, never a live registry entry — so this
+ worked example cannot PRIME a real prune. Apply the same shapes to real IDs.)
 
 [A. Obsolete — mark superseded]
-  BDR-003 — Gitignore wildcard pattern — status: proposed since 2026-03-12
+  BDR-901 — example proposed decision — status: proposed since <90+ days ago>
             → mark: status: deprecated (no follow-up after 90 days)
-  BDR-011 — Client handover 4-chapter — body says superseded by BDR-013
-            → fix Index: status = "superseded by BDR-013"
+  BDR-902 — example decision — body says superseded by BDR-903
+            → fix Index: status = "superseded by BDR-903"
 
 [B. Similar — merge]
-  LRN-014 + LRN-016 — both pandoc rendering quirks
-            → propose: merge into NEW LRN-017 ("Pandoc rendering quirks")
-              with both bodies appended + caveman pass; sources marked
-              status: superseded by LRN-017
+  LRN-901 + LRN-902 — SAME concept (two notes on the identical bug)
+            → propose: merge into NEW LRN-904 with both bodies appended +
+              caveman pass; sources marked status: superseded by LRN-904
+            (merge ONLY same-concept entries — complementary/different-angle stays split)
 
 [C. Bloated — inline caveman rewrite]
-  BDR-011 — body 612 words, filler density 7.2% → ~380 expected (-38%)
+  BDR-902 — body 612 words, filler density 7.2% → ~380 expected (-38%)
 
 [D. Index drift]
   (none)

skills/prune-memory/tests/BACKLOG.md

@@ -19,7 +19,15 @@ behavior on real registries.
 - GREEN: fictionalize the SKILL.md example (obviously-fake IDs, or an
   explicit "hypothetical" framing) so example IDs cannot match real entries.
 
-Status: filed, not built. Surfaced by the real-data A-measurement.
+Status: RESOLVED 2026-06-29. VERIFY-FIRST done — the real LRN-014 (pandoc header-id
+stripping) and LRN-016 (pandoc checkbox CSS overlap) are COMPLEMENTARY (different
+angles), NOT overlapping: the SKILL.md example modeled a *wrong* merge AND used live
+IDs that primed it on real data. GREEN: the whole STEP-2 example fictionalized to 9xx
+IDs (cannot match any live registry) + the merge example now models a same-concept
+merge with an explicit "merge ONLY same-concept" note. Closed by a DETERMINISTIC test
+(run-deterministic.sh RED-7: the STEP-2 example must carry only 9xx ids) — not the
+flaky behavioral fixture originally proposed, per LRN-046 (deterministic oracle >
+semantic judge on a destructive skill). Test caught its own ugrep false-green first.
 
 ## RED-8 (candidate) — added-negation inversion (documented limit, not a test yet)
 The RED-5 fidelity guard flags negation/permanent token DROPS; it cannot catch
@@ -35,4 +43,12 @@ requires ADDING a word, contrary to an operation that shortens.
 - RED (if pursued): assert no op INCREASES an existing entry's negation count.
 - Caveat: must exclude new/merged-entry ids (HEAD count 0 -> N is legitimate),
   so an increase-check needs care to avoid its own false positives.
-Status: documented limit, not built (low practical risk + non-trivial FP risk).
+Status: CONSCIOUSLY ACCEPTED as a documented limit 2026-06-29 (re-reviewed, not built).
+Rationale held on re-read: (1) remote — caveman/merge SUBTRACT tokens; authoring a new
+negation runs against the operation; no evidence in the real-data measurement (the
+"+7 not/no" in EVAL-006 is new/merged-entry ids going 0→N, NOT an existing entry
+inverted). (2) An FP-safe increase-check is non-trivial: the census only emits non-zero
+counts, so a 0→1 ADD produces a working-line with NO HEAD-line to compare — catching it
+needs the HEAD entry-id set to exclude legitimately-new/merged ids. A noisy increase-check
+= a guard you learn to ignore (LRN-047), worse than the honest documented limit on a
+destructive skill. Revisit only if a real inversion is ever observed.

skills/prune-memory/tests/run-deterministic.sh

@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-# Deterministic RED suite for /prune-memory — RED-1, RED-2, RED-5, RED-6.
+# Deterministic RED suite for /prune-memory — RED-1, RED-2, RED-5, RED-6, RED-7.
 # Each MUST be red on the current (v1) skill. Pure mechanical oracles,
 # no LLM. Faithful: RED-2/RED-6 execute the REAL bash blocks extracted
 # from SKILL.md (no copy that could drift).
@@ -83,6 +83,21 @@ else
   green 6 "verify does not false-orphan the title-less heading"
 fi
 
+# ---- RED-7: STEP 2 plan example must use FICTIONAL ids, never live registry ids
+# Live ids in the worked example PRIME the skill to act on those exact entries on
+# real data (observed 2026-06-25: it merged the example's LRN-014 + LRN-016 on the
+# live learnings.md, though they are complementary, not overlapping). Fictional ids
+# (9xx) cannot match a real registry. Reads SKILL.md only — sandbox-safe.
+# /usr/bin/grep (not the system grep, which may be ugrep — a leading-dash pattern
+# like `-9..` is then misparsed as an option, erroring to an empty + FALSE GREEN).
+ex7="$(awk '/^PRUNE PLAN/{f=1} f{print} /^Approve per category/{f=0; exit}' "$SKILL")"
+bad7="$(printf '%s\n' "$ex7" | /usr/bin/grep -oE '(BDR|LRN|BLK|EVAL)-[0-9]+' | /usr/bin/grep -vE '9[0-9][0-9]$' | sort -u | tr '\n' ' ')"
+if [ -n "${bad7// /}" ]; then
+  red 7 "STEP 2 example uses LIVE-range ids (prime real-data ops): ${bad7% }"
+else
+  green 7 "STEP 2 example uses only fictional (9xx) ids"
+fi
+
 echo "----"
 if [ "$fail" -eq 0 ]; then
   echo "SUITE: all GREEN"