A case-sensitive string HERMES.md in git commit messages silently reroutes Claude Code API requests from Max plan quota to extra usage billing.
Key Takeaways
Trigger is the exact string HERMES.md in recent git commit history, which Claude Code includes in its system prompt — not a file on disk.
The mismatch is case-sensitive: hermes.md, HERMES, HERMES.txt, and AGENTS.md all route correctly to plan quota.
Affected user hit a $200.98 extra usage charge while Max 20x plan showed 86%+ weekly capacity remaining — zero in-product warning.
Error message “out of extra usage” gives no indication that commit message content is the routing cause, making diagnosis extremely hard.
Minimal reproduction requires only a git init and one commit with HERMES.md in the message — no project files, no special configuration.
Hacker News Comment Review
Anthropic’s support response explicitly stated it cannot issue compensation for technical errors causing incorrect billing routing — commenters across the thread called this policy unprecedented and legally questionable.
Multiple commenters reported separate, independent billing incidents (triple charges, double auto-reloads) where refusals were only resolved via credit card disputes, suggesting a pattern beyond this bug.
Consensus is that Anthropic tends to take a hard initial policy position and then quietly reverse it, but the pattern of refusals before reversal is itself damaging and operationally unacceptable for teams running agents at scale.
Notable Comments
@mikehearn: “Not sure I’ve ever seen a company openly take this position” on refusing refunds for their own billing routing errors.
@evo_9: Reports a separate $100 double-charge incident where support never followed up — resolved only through a credit card dispute.
@sandeepkd: Raises whether billing overcharges caused by code errors expose Anthropic to legal liability.
