Claude Code billing bug triggered by "HERMES.md" in git commits
A Reddit user discovered that the exact string "HERMES.md" (uppercase, with `.md` extension) in recent git commit messages silently bypasses Claude Code's Max plan quota and routes all usage to extra API-rate billing, costing them $200.98 in unexpected charges.
Score breakdown
Check your git commit history for the exact string "HERMES.md" and review your extra usage at claude.ai/settings/usage if you use Claude Code on a Max plan, as this bug can silently drain hundreds of dollars in unexpected API-rate charges.
- 01The exact string "HERMES.md" (uppercase, with .md extension) in a recent git commit message triggers the bug; lowercase "hermes.md", "AGENTS.md", "README.md", and "HERMES" without .md do not.
- 02Claude Code includes recent git commit messages in its system prompt, and something server-side misroutes billing when it detects "HERMES.md".
- 03The affected user was charged $200.98 in extra API-rate usage despite their Max 20x plan ($200/month) showing 13% weekly usage and 0% current session usage.
u/alexxxklepa on r/ClaudeAI describes discovering a billing bug in Claude Code where the presence of the exact string "HERMES.md" (uppercase, with `.md` extension) in recent git commit messages silently reroutes usage from the user's Max plan quota to extra usage billed at API rates. The user, subscribed to the Max 20x plan at $200/month, noticed the error message "You're out of extra usage. Add more at claude.ai/settings/usage and keep going" despite their plan dashboard showing 13% weekly usage and 0% current session usage. After exhausting standard troubleshooting steps and four rounds with an AI support bot, the user conducted their own binary-search debugging across repos and commit history to isolate the trigger.
The minimal reproduction involves creating a git repo with a commit message containing "add HERMES.md" and running a Claude Code prompt — which returns a 400 API error citing extra usage exhaustion.
The minimal reproduction involves creating a git repo with a commit message containing "add HERMES.md" and running a Claude Code prompt — which returns a 400 API error citing extra usage exhaustion. The same setup with lowercase "hermes.md", "AGENTS.md", "README.md", or "HERMES" without the `.md` extension all route correctly to the plan quota. The post includes a GitHub bug report filed at `https://github.com/anthropics/claude-code/issues/53262`. Anthropic's support acknowledged the "authentication routing issue" three times but refused to refund the $200.98 in incorrectly billed charges. The user flags that `HERMES.md` is a legitimate and common convention in AI agent projects for system prompt specifications, making this an issue that could affect a meaningful number of Claude Code users.
Key facts
- 01The exact string "HERMES.md" (uppercase, with .md extension) in a recent git commit message triggers the bug; lowercase "hermes.md", "AGENTS.md", "README.md", and "HERMES" without .md do not.
- 02Claude Code includes recent git commit messages in its system prompt, and something server-side misroutes billing when it detects "HERMES.md".
- 03The affected user was charged $200.98 in extra API-rate usage despite their Max 20x plan ($200/month) showing 13% weekly usage and 0% current session usage.
- 04Anthropic support acknowledged the bug as an "authentication routing issue" three separate times but refused to issue a refund.
- 05A bug report was filed at github.com/anthropics/claude-code/issues/53262.
- 06HERMES.md is a real convention in AI agent projects used as a system prompt specification file, making this a non-obscure edge case.