# `[2026-08-26]` Run 3 corpus built, then held — and the megamix containment defect it exposed Run 3's corpus was built to brokkr's `SFT-RECIPE-run3.md` (`f6c0589`), a blocker was found before any GPU spend, and **brokkr is now redoing the recipe**. Nothing launched. The build artifacts survive and are re-parameterisable. ## ⚠ THE FINDING: `creative-writing-multiturn` is a MEGAMIX containing our other roots Its own Hoard card says so — `hoard/datasets/creative-writing-multiturn/dataset.yaml`, `archive_provenance_note`: > *"Dampfinchen/Creative_Writing_Multiturn — 2026 curated ~4.6k high-turn > creative-writing/RP **megamix (bluemoon, LimaRP/PIPPA, stheno, gutenberg-dpo > chosen, VellumK2 subset)**"* **It is not a sibling root. It is a bag holding several of our other roots.** Found because my corpus build would not reproduce brokkr's numbers: he computed on the raw roots, I computed on run 1's deduped survivor list. bluemoon came out 67 against his 126. Run 1's dedup record explains it: DROPPED -> KEPT n median jaccard bluemoon -> creative-writing-multiturn 59 1.000 creative-writing-multiturn -> pippa 30 1.000 c2-logs-32k-llama3 -> creative-writing-multiturn 23 0.945 brokkr then measured it directly against the raw corpora, and it is worse than the dedup threshold showed — **the MEDIAN bluemoon conversation is 87% similar to something in creative-writing** (≥0.99: 28.3%, ≥0.90: 49.6%, max 0.999). That is containment, not overlap. **Why it mattered here specifically:** the remix elevates creative-writing to 43.2% and bluemoon to 31.4% of loss signal — *the two roots that overlap*. Building on raw roots would have double-counted bluemoon inside creative-writing's share, in a run whose entire justification is the composition change. ## Three consequences, two of them structural **1. "bluemoon is the only human-authored root" was overstated.** It is the only *wholly* human-authored root; creative-writing is *partly bluemoon*. brokkr restated rather than withdrew. **2. ⚠ F1 does not do what the recipe says.** "Excise PIPPA" removes the ROOT, not the MATERIAL — PIPPA persists inside the megamix, which the remix promotes to largest contributor. **F2's 250-word floor is what actually removes PIPPA material**, because PIPPA turns cannot exceed 123 words wherever they live. The outcome was right; the stated mechanism was wrong. **Had the operator chosen a floor below 123, F1 would have been nearly cosmetic.** **3. ⚠ The dedup kept the wrong side of the pair, 59 times.** When a primary source and a megamix containing it collide, the survivor should be the primary source, not the copy inside the bag — the megamix version may have been reprocessed by its curator. We kept the derivative and discarded the origin. **Reversed for run 3** (brokkr's call, ~3 minutes): keep bluemoon, drop the megamix copy. Result is better than either prior version — root run 2 recipe DEDUPED+REVERSED bluemoon 6.9% 31.4% 38.6% creative-writing 18.0% 43.2% 30.4% c2-logs 40.2% 25.4% 31.0% pippa 34.9% 0% 0% **The wholly-human share went UP and the megamix share went DOWN** — strictly the composition the recipe argued for, now honestly counted. Total context unchanged at 12.49M, so the operator's settled mix arithmetic survived untouched. ## ⚠ The catalog-level problem, unsolved **A megamix root silently contains other catalog roots and nothing in the mix arithmetic knows.** Any share computed over roots including creative-writing double-counts bluemoon, PIPPA, LimaRP and stheno by an unknown amount. Run 2's mix had this defect and nobody noticed, because run 2 did not promote the overlapping roots. LimaRP and stheno are **still unchecked against anything.** Wants a `contains_datasets:` field on the Hoard card plus a preflight assertion that no recipe includes both a megamix and a root it contains. brokkr is raising it as its own item; not a run-3 blocker. ## What is staged on ana-ml2 /tank/erp-tune/recipe-r3/recipe-erp-seat-sft-r3.json /tank/erp-tune/recipe-r3/dialogue-survivors.jsonl 610 conversations /tank/erp-tune/recipe-r3/lowquality-mask-v1.jsonl 5,867 mask rows /tank/erp-tune/build_r3.py the filter build; floors are constants at the top /tank/erp-tune/pippa_clip.py length-distribution measurement /tank/erp-tune/clip_share.py turn-share vs word-share ⚠ **`/mnt/smithy` is READ-ONLY from ana-ml2**, so recipe artifacts live under `/tank/erp-tune/recipe-r3/` rather than beside the r1 recipe. The harness takes absolute paths, so this is fine — but do not expect to write to the r1 recipe dir. **F2/F3/F4 are implemented as a LOSS MASK reusing the impersonation-mask format**, so `load_impersonation_mask` reads it and `_impersonation_flags` sha-asserts every masked turn with no new harness code. F4 is masked rather than stripped: stripping mutates content, which invalidates the shas, and the read-only mount forecloses a mutated derived root anyway. 28 turns of 6,209 (0.45%). Re-parameterising for a new recipe is one command and ~90 seconds; the dedup reversal and F4-as-mask handling are baked in and survive it. ## Decisions I took **No conversation admission threshold** (brokkr delegated it, then endorsed). 81% of surviving bot turns are context-only, but masked context costs the transformer body and **not** the LM head — the harness drops `IGNORE_INDEX` before the 262k-vocab head, so the waste is bounded well below what the 81% suggests. A 20% context trim buys ~35 minutes against a 3-hour run, and it would be a fifth filter moving composition inside a run whose purpose is testing the filters alone. **Buying 35 minutes by confounding a 3-hour experiment is a bad trade.** brokkr: "your reason 1 is decisive." **Left `erp-tune-v2` UP** on the operator's discretion grant. The card is not needed until a recipe is settled, and it is his evaluation surface plus a live gateway route. Take it down when run 3 is actually ready, not before.