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Swap a for 4

instruction-following · GPT-5.4 nano · GPT-4.1 nano · Claude Haiku 4.5

The prompt (verbatim, sent to every lane)

Rewrite this sentence replacing every letter "a" or "A" with the digit 4: A banana always attracts attention.
How scoring works

Exact match: 4 b4n4n4 4lw4ys 4ttr4cts 4ttention. — trailing period required; it's in the source sentence. Failures show a character-level diff. Scoring strips leading/trailing whitespace and one wrapping pair of code fences or quotes before it judges — content over ceremony. Winner rule: correct → cheapest → fastest.

Prices as listed by OpenAI and Anthropic, July 2026. Costs come from provider usage fields × list prices — nothing is invented.