Unverified50% confidenceBenchmarkExact time
When asked to "Output nothing. Return an empty string.", Haiku 4.5 returned an empty code block 21 out of 22 times, while Haiku 5.5 returned a truly empty string in all 22 times.
1
Sources
50%
Confidence
Medium-term (~90 days)
Relevance
10/18/2026
First Seen
Valid until: 1/16/2027
Sources
Related Entities
Related Claims
UnverifiedAmong the 15 prompts that permit refusal, Haiku 4.5 consistently refused 8 per day, while Haiku 5.5 fluctuated between 5 and 8.63% similarUnverifiedAt temperature 0, Haiku 4.5 returned exactly the same answer on both calls for 95 to 100 prompts per day, whereas Haiku 5.5 did so for only 41 to 49.62% similarUnverifiedClaude Haiku 5.5 uses a new tokenizer that produces about 30% more tokens than Haiku 4.5 for the same text.57% similarUnverifiedIn a test of 340 Japanese support tickets, 29 (8.5%) escaped prompts had at least one character error, while only 3 (0.9%) of the raw UTF-8 prompts did.51% similar
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