Claude Code's eval grader can't see a no‑break space

说明与用途

AI 评估工具无法识别 U+00A0 无断空格，导致对严格空格处理的代码评估错误。向答案中添加不可见字符列表可修复此问题。

问题

AI grading tools misinterpret no‑break spaces as ordinary spaces, causing incorrect pass/fail decisions on coding tasks that require strict whitespace handling.

结果

Adding an explicit list of invisible characters to the answer text enabled AI graders to correctly interpret whitespace, raising accuracy from 0/6 to 6/6 for multiple models.

工作流

• 1. Identify a coding question that involves strict whitespace handling.
• 2. Provide two candidate answers, one correct (Answer A) and one incorrect (Answer B).
• 3. Run the answers through multiple AI grading tools and record their decisions.
• 4. Observe that graders misinterpret no‑break spaces and fail to detect hidden characters.
• 5. Add a short note to the answer that enumerates the invisible characters with line/column and Unicode code point.
• 6. Re‑run the grading tools; all now correctly evaluate the answers.
• 7. Submit the fix as pull requests to the relevant open‑source projects.

证据

The task says to refuse it. A refuses it, so its test says False.

来源

The graders got 0 of 6 right with Haiku 5.5 and 1 of 6 with Sonnet 5.5.

来源

The fix is deliberately small. Alongside the answer, a short note lists any unusual spaces and invisible characters, with their exact position.

来源

All graders correctly evaluated both answers.

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