diff --git a/docs/cookbook-index.md b/docs/cookbook-index.md
index 7d0c5a4c34..d663f0579f 100644
--- a/docs/cookbook-index.md
+++ b/docs/cookbook-index.md
@@ -2,7 +2,7 @@
 
 > **Generated by `tools/cookbook_index.py` — do not hand-edit** (R33). Regenerate after adding a cookbook section.
 >
-> `docs/matching-cookbook.md` is ~716 KB / 1153 sections. Grepping it blind is how three P30 wave-1 agents each "discovered" an idiom that was already written down. **Start here, then read the section.** A section appears under every symptom it addresses.
+> `docs/matching-cookbook.md` is ~716 KB / 1154 sections. Grepping it blind is how three P30 wave-1 agents each "discovered" an idiom that was already written down. **Start here, then read the section.** A section appears under every symptom it addresses.
 
 **How to use:** name what you SEE in the diff (a stolen delay slot, an extra `la`, a swapped register pair, a `conflicting types` error), find that symptom below, read those sections first. If nothing fits, THEN grind — and add a section when you win.
 
@@ -839,7 +839,7 @@
 - **§3-B.** — A SINGLE-SET LOCAL'S VALUE IS VISIBLE AT A SWITCH JOIN, AND THAT ERASES A ZERO-EXTENSION (CONFIRMED: `ov_SC03_105:func_801806F8`, 241 ins, banked from closeness 235)  <sub>L34975</sub>
 - **§3-D.** — AN OFFLINE JTBL-RODATA PLACEMENT AUDIT (CLAIMED: `md_MAIN_034:func_800CB00C` — did NOT bank, and that is the point)  <sub>L35008</sub>
 
-### optimisation level (-O0/-O2)  (24)
+### optimisation level (-O0/-O2)  (25)
 
 - **§6** — Per-module optimization mixing — the -O0 boot module (Phase 7)  <sub>L265</sub>
 - **Detecting** — the opt level (do this first)  <sub>L273</sub>
@@ -865,6 +865,7 @@
 - **§388** — ★★★ — THE **-O0 COLOURING ORACLE**: simulate `stupid.c` instead of grinding spellings (P31 S69; main/func_80011380 proved a C-level WALL at 6)  <sub>L32384</sub>
 - **§466** — `main` (509 ins, -O0): ADDRESS CONTEXT EMITS `mult` INDEX-FIRST  <sub>L35310</sub>
 - **§474** — A *PROVED* C-LEVEL FLOOR: `split_tree` + `stupid.c` (-O0), from `main:func_80011380`  <sub>L35544</sub>
+- **§486** — ★★★ — CARVING AN `-O0` ISLAND IN **main**: FIVE COUPLED PIECES, AND THE TWO THAT ANNOUNCE THEMSELVES (P31 S77)  <sub>L36105</sub>
 
 ### family propagation & sweeps  (123)
 
@@ -2927,6 +2928,7 @@
 - **§483** — ★★★ — THE S77w WAVE HARVEST: SIX LEVERS, FOUR FROM BANKED (BYTE-PROVEN) BODIES  <sub>L35967</sub>
 - **§484** — ★★★ — "NO SINGLE NOLOAD BASE" IS NOT "UNLINKABLE": ASK WHETHER THE `.bss` OFFSETS ARE DISJOINT (P31 S77)  <sub>L36023</sub>
 - **§485** — ★★★ — THE PLACEMENT MAP WAS PARSING A PRETTY-PRINTER: 25 PsyQ OBJECTS WERE INVISIBLE, NOT ABSENT (P31 S77)  <sub>L36069</sub>
+- **§486** — ★★★ — CARVING AN `-O0` ISLAND IN **main**: FIVE COUPLED PIECES, AND THE TWO THAT ANNOUNCE THEMSELVES (P31 S77)  <sub>L36105</sub>
 
 
 ---
@@ -4092,3 +4094,4 @@ Notes routinely quote that as a section id. This table resolves it. Grep bait: `
 | L35967 | §483 | ★★★ — THE S77w WAVE HARVEST: SIX LEVERS, FOUR FROM BANKED (BYTE-PROVEN) BODIES |
 | L36023 | §484 | ★★★ — "NO SINGLE NOLOAD BASE" IS NOT "UNLINKABLE": ASK WHETHER THE `.bss` OFFSETS ARE DISJ |
 | L36069 | §485 | ★★★ — THE PLACEMENT MAP WAS PARSING A PRETTY-PRINTER: 25 PsyQ OBJECTS WERE INVISIBLE, NOT  |
+| L36105 | §486 | ★★★ — CARVING AN `-O0` ISLAND IN **main**: FIVE COUPLED PIECES, AND THE TWO THAT ANNOUNCE  |