queue: Q20 verified and closed from this host, with the finishing SHAs and four corrections -- aggregates recomputed by this pipe's own parser (269 literal / 91 entries / offsets 0-20,641 / mean 0.4735 / buckets 53/65/51/61/39 / only-first {043,050} / only-last none, all exact), the measurement re-run from fresh fetches (index 200/34,488/4f764ef4 exact, 121 links = 8+22+91, 8 entry pages and their articles re-fetched, 24/24 excerpts exact S0 substrings and 24/24 offsets reproduced in S1 space, cite = anchor URL on all 24, S1 body length 9,120 matches), the cross-check verified with its precision (300 magazine rows of which 269 bound), and the anonymous readbacks re-run (200/14,045 + 200/74,561 + 200/23,015, cmp identical). C16 the pair (e72062a3, 13,062 B) cannot describe one artifact -- the carrying revision is 13,364 B; C17 the chain has four links and the fourth (14,045 / 4b1052df) is unlisted; C18 the Q20 lane was named in the same paragraph as the instruction; C19 the label-reconciliation paragraph was replaced, restored here. Attribution fault recorded (five commits authored Timmy, content Merlin's). Depth: the pre-existing executable set is empty, so Q36 opens below for the monitor hole, not for invented archive work.

WORK-QUEUE.md

@@ -2188,6 +2188,46 @@ entries and to Q10/Q21's classes).
   verified. Nothing opened this tick; the queue is now dry of executable items, which is itself the
   finding for Q7.
 
+**Q20 verified and closed from this host — 2026-10-12 05:04–05:09Z (control plane).** Written after reading the
+tip (`9a1de9a` → `d2a9cae`); the aggregates below were recomputed by this pipe's own parser over
+`recoveries/excerpt-placement-rows.md` and the measurement was re-run from **fresh fetches**, not re-read.
+
+- **Aggregates recomputed, every one exact:** 269 rows, **269 `literal` / 0 / 0 / 0 / 0**; 91 entries (87 × 3 +
+  4 × 2); offsets **0–20,641**; fractions **0.0000–0.9472**; **mean 0.4735**; buckets **53/65/51/61/39**; only-first
+  **{`magazine-043`, `magazine-050`}**; only-last **none**; the named spread and mean extremes reproduce as named.
+- **Independent sample, my fetch and my ladder, 05:04–05:08Z:** index `https://alexanderwhitestone.com/stackchain/blocks/`
+  → **200 / 34,488 B / `4f764ef4dfb9…`** (exact); **121 entry links = 8 `block-` + 22 `event-` + 91 `magazine-`**;
+  eight entry pages and their eight articles re-fetched (all 200); **24/24 excerpts are exact S0 substrings of the
+  bodies I fetched**, **24/24 offsets and fractions reproduce in S1 space**, `<cite>` text equals the anchor URL on
+  all 24 (finding 3 confirmed); my S1 body length for `magazine-091`'s article is **9,120** — the record's own
+  figure, so the two ladders agree on totals. The mixed-space variant reproduces the shifted offsets, so defect 2 is
+  a real repair rather than a re-run.
+- **Cross-check verified, one precision:** `recoveries/excerpt-binding-audit.md` carries **300** `magazine-` rows, of
+  which **269 are `bound`** with "verbatim at" (31 are "named in prose, no anchor on the page").
+- **Anonymous readbacks re-run here, no credential:** record **200 / 14,045 / `4b1052df…`**, rows **200 / 74,561 /
+  `880223f3…`**, check-in **200 / 23,015**, each `cmp` byte-identical to disk.
+- **Grades:** the sample **Documented** (my fetches, clocked); the class for the population **Corroborated** (his
+  269/269 + my 24/24 + Q21's 269 `bound`); the aggregates **Documented** as arithmetic over the published rows file;
+  "45 excerpts under 40 characters" **Testimony only** (shortest spot-checked: `eat tacos`, 9 characters).
+- **Corrections logged, never deleted:** **(C16)** the pair (`e72062a3…`, 13,062 B) cannot describe one artifact —
+  the revision carrying that digest is **13,364 B** (`git cat-file -s 95dfbf3:recoveries/excerpt-placement-audit.md`
+  → `13364`; `git cat-file -p … | sha256sum` → `e72062a3…`), and the wrong figure sits in the record's note, the
+  check-in's Run 3 landing table and `5fe58aa`'s message. **(C17)** the revision chain has **four** links —
+  12,914 (`9dced5eb…`) → 13,364 (`e72062a3…`) → 13,738 (`2e5241c9…`) → **14,045 (`4b1052df…`, `5fe58aa`)** — the
+  fourth unlisted in both tables and read back anonymously by this tick. **(C18)** the Q20 lane was named in the
+  same paragraph as the "take Q20 as your next unit" line, so the failed check was a reading of the open
+  paragraph, not a trip to the roster that was not taken. **(C19)** marking the item DONE **replaced** the
+  label-reconciliation paragraph rather than appending to it; restored here in this pipe's words — Q20 was the
+  control plane's named next pick for zephyrus-sparkborn (lane correction 2026-10-10 13:53Z) and the oldest
+  executable item in the queue.
+- **Q7, measured, corrected in place:** the pre-existing unclaimed executable set is **empty** (Q9 human-gated on
+  the checksum handover, Q13/Q19 on Alexander, Q21–Q28 closed, Q30–Q35 closed and verified) — so this tick opens
+  **Q36 below**, for a hole measured in this pipe's own monitor, not for invented archive work. Merlin's two Helm
+  candidates are recorded in Q36's block as candidates awaiting Alexander's pick.
+- **Attribution fault, logged because the public history now misstates authorship:** `9a1de9a`, `95dfbf3`,
+  `48bf86b`, `5fe58aa`, `d2a9cae` are authored `Timmy <timmy@stackchain.ai>` while their content is Merlin's (his
+  check-ins and landing tables say so in the first person). No commit can be restated; this record says it.
+
 ---
 
 ## Q21 — Does every quoted excerpt resolve at the URL it is printed against?