Anthropic Claude Code Overcharged User $200.98 Due to Billing Bug, Initially Denied Refund Before Full Compensation

According to monitoring by Beating, a billing bug in Anthropic's Claude Code service caused a Max 20x subscriber to be overcharged $200.98 in extra usage fees while only using 13% of their monthly quota. The bug was triggered when a user's git repository commit history contained the uppercase string "HERMES.md"; the system bypassed subscription limits and charged additional usage instead. Anthropic's abuse prevention system was performing string matching on git logs injected into system prompts, likely attempting to detect unofficial API clients, but mistakenly flagged legitimate users mentioning the Hermes Agent configuration file.

After the user submitted a refund request, Anthropic's AI customer service initially denied compensation, stating it could not refund for billing routing errors. The denial sparked backlash on GitHub and Hacker News, reaching the front page. Claude Code team member Thariq subsequently announced that all affected users would receive full refunds plus equivalent credit compensation.