Error: no header row with name
Name the column with students Student (or Name), then run again.
A student is skipped with 'no mark'
Their mark cell is empty. Add the mark and run again.
Pronouns are wrong
Add a Pronoun column (he, she or they). Without it, 'their' is used.
Claude does not use the skill
Check it is switched on in Settings → Capabilities → Skills, then name it in your message.
The script says a column is missing
Rename your header to one of the names in README, or say the mapping in your message.
Code execution is off
Skills with scripts need code execution enabled in Claude.ai settings.
FAQ
Does it use AI or send student data anywhere? No. Comments are built from a fixed comment bank on your own computer or Claude session. No network calls; nothing is sent.
Can I use the comments as they are? They are first drafts. Read and adjust each one: you know the student, the bank does not.
Which marks work? Percentages (0-100) or letter grades A to F. Bands: 85+ excellent, 70-84 secure, 50-69 developing, below 50 support.
Is the free version limited? One mark column, up to 40 students, the built-in bank and 600 characters. No account and no cap on runs.