Leave length unset on a sum
2026-03-16 · Arithmetic captchas
The result can be one digit or three. A fixed length will force a wrong width.
9 + 1 is 10, two characters. 3 + 1 is 4, one character. length: 2 makes the second of those impossible to return correctly.
Never copy a numeric portal's length: 6 into a math call by habit. Options should be chosen per captcha type, not per HTTP helper.
If your client has one function for every portal, pass an options object from the portal config. A boolean math in that config is safer than a global default.
Batches that mix sums and codes must override options per item. A top-level length would hit the sums too.
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