AGENTS.md: document designation scanner session

AGENTS.md

@@ -171,7 +171,45 @@ Each pass has quality gates. Quality is the primary concern; generation speed is
 
 ## Current Session Summary
 
-### Session: Speaker designation + discovery over-detection (spec 17 §3.1/§3.2 + rules)
+### Session: Designation scanner — capture the ch5 speakers discovery missed
+- **Discovery re-run on ch5 with the new over-detection prompt rules** (`gemma-4-e4b`,
+  ~22 tok/s; stopped Qwen TTS first per the no-co-residency rule, restarted it after).
+  It **improved** — found "The big one", "The one on the left/right", "The Leader",
+  "Girl helping" where it previously found none — but **still dropped "The oldest" and
+  "The tallest"** from the same six-man crowd. The small model is not deterministic enough
+  to guarantee coverage, so a mechanical backstop was added.
+- **New `umbraaudio/analysis/designation_scan.py`** (no LLM) reads the three canonical
+  speech-attribution shapes and harvests every designation a speaker is referred to by:
+  `"The oldest says,"` / `"I thought they died off," says the tallest` / `"No," the old smith said.`
+  Post-filters: pronouns, narration verbs (`Hallr Grips His Axe And`), finite-verb clauses
+  (`Treasure Is One`), possessives (`Hallr's`→`Hallr`, `Sheyla's voice`→`Sheyla`), bare
+  articles, indefinite collectives, and **tags inside a quotation** (someone being talked
+  ABOUT, not speaking). Reads chapter `source_text` (not utterances) so it runs before
+  attribution.
+- **New `scripts/merge_designations.py`**: adds uncovered designations as `unidentified`
+  speakers with evidence. Never removes/rewrites existing entries, atomic tmp+replace,
+  idempotent (0 on re-run). **`--dry-run` first, always.**
+- **New `scripts/run_discovery.py`**: runs discovery to a **separate output file** so a
+  discovery run can never overwrite the curated `speakers.json`.
+- **Result: Last Dwarf cast 70 → 93.** 56 designations, 33 already covered, **23 genuinely
+  missing** — the ch5 crowd (The Oldest, The Tallest, The Young One, The One With The
+  Biggest Sword, The Biggest One, The Leader, One Girl Helping) plus **Manfred** (a real
+  missing speaker!), The Sergeant, One Witch, The Soldier, One Rider, One Lieutenant etc.
+  All 23 land at 0.00 confidence / "needs check" so the reviewer triages them.
+  Speakers page now: **93 rows, 31 clear / 62 need checking**.
+- **Regex lessons worth keeping**: `sings?|sang` matched INSIDE gerunds ("Relea**sing**",
+  "Clo**sing**", "Sen**sing**", "Pas**sing**") until a leading `\b` was added before the
+  verb alternation; `The Guard` captured as just `Guard` until continuation words allowed
+  capitals; appositives ("The biggest one, a healthy farm boy, says") need `\s*` not `\s+`
+  before the comma. A narration-verb blocklist in `_is_designation` is far more maintainable
+  than a giant allow-list regex.
+- Commit `4775e3b`. 14 new tests. Full suite **461 passed** (8 pre-existing/parallel).
+- **NEXT (Phase 5)**: re-run `scripts/reattribute_all.py` — the utterances currently
+  labelled "Walking oldest"/"scum leader" should re-point to the new clean names now that
+  they exist as profiles. Note "The Big One" vs "The Biggest One" are the same person and
+  need a merge (the designation system flags the pair).
+
+### Previous Session: Speaker designation + discovery over-detection (spec 17 §3.1/§3.2)
 - **Trigger**: reviewer reported obvious speakers missing from Last Dwarf (the six men
   in ch5 identified only as "the oldest"/"the tallest"/"the young one"/"the one with the
   biggest sword"; the scum group), which they had to add by hand. And: "I would rather