You do not set the confidence cutoff
2026-01-24 · Captchas
The service decides reliable from a fixed threshold per engine. Log the score, and branch on the flag.
confidence is a number between 0 and 1 from the decoder. It is useful in your logs when a portal later rejects an answer. It is not a knob.
There is no request field for a custom threshold. The published cutoffs are 0.8, 0.7, and 0.5 for text, math, and Hindi. Changing them yourself by ignoring reliable means you will type answers the service refused to charge for, which is the set that is wrong more often.
On the measured sets, reliable answers were righter than the raw set. Numeric codes were 88.3% correct overall and 98.1% correct among reliable answers. Arithmetic was 95% overall and 98.3% among reliable answers.
Trust the flag. Refresh when it is false.
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