What are the character limits for AI slash commands in the composer?
Two limits apply. The instruction you type after / must be 1000 characters or fewer, and the draft in the composer must be 2000 characters or fewer.
If either limit is exceeded, the request fails and the composer shows the message "Failed to generate or edit message." There is no character counter in the composer to warn you before you hit a limit.
The two limits are checked separately. The instruction and the draft are sent to the AI as separate inputs, so a short instruction on a long draft still fails if the draft is over 2000 characters.
What to do if you hit a limit
If the instruction is over 1000 characters, shorten it. For complex edits, split the work into several shorter slash commands: run one, review the result, then run the next.
If the draft is over 2000 characters, it is too long for the AI to process. Shorten the draft before running the command, or split the reply into shorter sections and edit each one separately.