Dated experiment record. Statements describe this run, not current submission readiness. Historical H. pylori category names do not establish infection; copy screens are bounded tests. Claims that a source does not exist mean none was identified in that recorded search, not proof of absence. Licensing interpretations in the notes remain unconfirmed. Local access details have been omitted. Current limitations and remaining work.

Q2 tissue-prompt ablation gate

Post-hoc invalidation (2026-08-27): the upstream LoRA was trained with held-out-slide leakage. This remains an exploratory prompt-control record only; it cannot support generalisation or checkpoint selection. See reports/SLIDE_SPLIT_AUDIT_REPORT.md.

Date: 2026-08-26 UTC

Run: 20260826T095638Z-prompt-ablation

Code: 2ed42eb97905706ce7e7b5a97482d85b225c3762

Result: FAIL for tissue-scaffold selection — the curved-object failure is suppressed, but positive-category morphology collapses toward nonspecific tissue

Frozen comparison

This ablation loaded the no-overlay epoch-3 checkpoint with SHA-256 5fb8d73646228a2eb047593113e6c64490c2fe2c6c9c71b803c04b64718e9de7. Width, height, steps, guidance, model, checkpoint, seeds, and normal/metaplasia positive prompts remained fixed. The two H. pylori-positive prompts were changed to request lesion tissue without visible organisms, and the negative prompt was strengthened against worm-like or thick curved objects. Prompt-override SHA-256 was 091d247a1badd4e4e72b0535609bb65eb6322f824ebf4eaa320d9947c99b86a7.

Mechanical, runtime, and privacy results

The run completed from 09:56:38Z through 10:05:31Z, or 533 seconds, with QWEN_PROMPT_ABLATION_COMPLETE and exit code 0.
All fourteen files in ALL_SHA256SUMS matched after retrieval. All four outputs decode as 1024x1024 RGB PNGs, and every generation-manifest record points to the frozen LoRA hash.
A100 uptime including startup and automatic shutdown was 735.278 seconds, at most about US$0.75 using the conservative US$3.673385/hour on-demand rate; the instance was Spot. The bounded CPU recovery worker ran for 543.165 seconds, about US$0.02 at US$0.134/hour. Both workers are terminated and all temporary recovery resources were deleted.
Privacy screening against the 128 no-overlay training fields passed: zero exact matches, maximum DINO cosine 0.951791 against the 0.995 threshold, and minimum dHash distance 17 against the distance-at-most-4 threshold. Privacy report SHA-256 is a01b1afe62742a163fdd5483fc671dcbdfb05891d6b8a238635aed93bd5f9505.

Morphology finding

The held-out/Q0/Q2-v1/no-overlay/prompt-ablation sheet SHA-256 is fe84106049f0e4cacffdaf68d038486c0384cb7e8079a9d981266359cfca45b3.

Removing positive organism wording suppresses the gross dark curved rods in both positive cells. This confirms that inference wording is a material cause of the shortcut.
The H. pylori-gastritis result becomes pale, diffuse, and poorly glandular, without convincing chronic-active inflammatory architecture.
The mixed result loses convincing goblet-cell/metaplastic and gastritis coexistence. It resembles nonspecific pale tissue rather than a mixed lesion.
Mean nearest-held-out DINO cosine is 0.919272, but every cell's nearest reference tile is from a normal or gastritis reference rather than preserving its requested category. The high aggregate value therefore reflects tissue texture, not category fidelity.
No organism-neutral tissue cell is submission-eligible, and the four-cell set fails the whole-checkpoint morphology gate.

Held-out diagnostic SHA-256 is 26fa8a10847aa6f2bed075c9885da791453a70c5c44965fa53c2f71558efbd03.

Gate decision

The experiment identifies a two-part failure: explicit organism wording drives oversized curves, while the existing checkpoint does not retain enough positive-category tissue signal when that wording is removed. The next bounded Q2 correction changes only the 64 positive-category training captions to organism-neutral gastritis and mixed-lesion descriptions. All 128 training pixels, slides, coordinates, provenance, split, model, optimiser, rank, learning rate, epochs, validation seeds, and normal/metaplasia captions remain fixed. Q3 remains blocked.

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