Billing anomaly in Claude Code linked to specific string in git history
The issue affects Max plan subscribers and remains unconfirmed by Anthropic
A billing anomaly has emerged within the Claude Code application, where API requests are incorrectly charged as extra usage rather than being covered by a user's included Max plan quota. The trigger for this error is the presence of the specific, case-sensitive string HERMES.md within a repository's recent git commit history.
When this string appears in the commit logs fed to the AI's context window, the billing logic appears to route the request to an overage meter instead of the standard plan allowance. This mechanism resulted in a reported silent charge of $200 in extra usage credits while the user's plan capacity remained largely unused.
The investigation into the discrepancy revealed that the trigger is the exact string HERMES.md appearing in git commit messages, not the existence of a file with that name on the disk. Claude Code includes recent commit history in its system prompt during code generation tasks, and the presence of this specific text seems to alter how the server-side billing system processes the request.
A user successfully reproduced the issue using a systematic binary search. By cloning affected repositories and isolating individual commit message strings, the specific trigger was identified. This method confirmed that the bug affects the billing logic for Max plan subscribers, causing requests that should be free to incur additional costs.
It is currently unknown whether Anthropic has acknowledged the bug or issued a patch. The exact scope of the bug, including how many users were affected and the total financial impact, is not yet quantified beyond the single reported instance. The specific server-side logic that causes the routing error when HERMES.md is detected has not been disclosed by the company.
The claim that the string HERMES.md specifically triggers the bug is based on a single user's investigation and binary search; it has not been independently verified by Anthropic or through broader testing by the community. The assertion that this is a silent charge relies on the user's observation, as other users may have noticed the discrepancy immediately.
Without official confirmation, the causal link between the string in the commit history and the billing route remains inferred. Other factors cannot be entirely ruled out, and it is unclear if Anthropic has issued a patch or if other users have experienced similar silent charges.
