When vibecoder patches a files, it tends to ignore the first line as seen from the duplicated import below (i.e., it didn't see import base64 in line 1)
The issue seems to be that the parser used by apply patch tool starts from index=1 here but the read file tool joins lines as zero-indexed list here
To repro: Just ask vibecoder to find an import bug in agent.py or call text_to_patch directly.
Wil send a PR to fix this.