Ran eval/opus-density/run.mjs against the API (harness shipped without committed
results). Issue #6 answer: Opus 4.8 exact-string recall rises monotonically as the
render gets less dense — 1/4 -> 3/4 -> 4/4 across 5x8/7x10/9x12, reaching 4/4 exact
with 0 confabulations at 9x12 (45% savings), byte-exact hex, stop_reason end_turn.
Density is the lever; not a DEFAULT_MODEL_BASES change.
Two response-reading bugs fixed (neither involves images):
- callModel read content[0].text, but always-on-thinking models put a thinking
block with empty text at content[0]; the answer is in a later block. Every Fable
answer read as "" and scored miss/confab. Fixed: select the text block;
max_tokens 128 -> 512.
- score() ignored stop_reason, so a refusal (HTTP 200, stop_reason "refusal",
empty content) scored as a confabulation, inverting the safety verdict. Fixed:
treat refusal as its own state; a refused guard is safe.
Adds results.json (live run), RESULTS.md (write-up), verify.mjs (confound-free
receipts for both fixes plus the guard-question caveat: the never-stated password
guard trips Fable's cyber classifier equally on text and image, n=6, so it is not
an imaging effect and is unmeasurable on Fable as written).
Deval Shah