Claude Code billing vulnerability exposed: If you write a typo in git commit, you will be overcharged $200, Anthropic has fixed it

Core conclusion

On April 30, 2026, Anthropic Claude Code was exposed to a serious billing vulnerability: as long as the commit message of the git warehouse contains the string HERMES.md, Claude Code will route the API request to the "extra usage billing" (pay-as-you-go) channel, bypassing the user's existing Max package quota. It has been confirmed that a user was overcharged $200.98 as a result.

Key Points

• Time of incident: 2026-04-30 -Affected: All Claude Code Max/Pro subscribers
• Core change: Anthropic's abuse detection system was accidentally triggered, using text matching in git commit history as the basis for billing routing
• Anthropic has officially confirmed the fix and promised a full refund + an additional one-month subscription as compensation.

Background and trigger events

The controversy started with a bug report submitted by GitHub user @sasha-id in Anthropic Claude Code Issues. He found that his Max 20x package ($200/ months) showed only about 13% of weekly usage, but suddenly it prompted "You're out of extra usage..." and could not continue to use it. After checking the bill, I found that I was charged an additional $200.98.

After repeated investigations, he found an incredible trigger condition: As long as the string HERMES.md appears in the commit history of the warehouse, Claude Code will route the request to the additional billing channel.

Note: This is not a file called HERMES.md, but the commit message contains this word.

Technical Analysis: Trigger Conditions and Avoidance

Precise trigger conditions

After repeated testing by the community, the confirmed trigger boundaries are as follows:

**Conclusion: The triggering condition is an exact match of the case-sensitive HERMES.md string in the git commit message. **

Root cause analysis

Boris Cherny, head of Anthropic Claude Code, responded on GitHub:

"This was an overly sensitive abuse detection system. Fixed."

Claude Code will send the recent commit history of the warehouse to the Anthropic server in the context of system prompts with each request. There is an anti-abuse system on the server side that specifically detects whether a third-party Agent tool framework (such as Nous Research's Hermes Agent) is being used, and routes such requests to the pay-as-you-go "extra usage" channel instead of the monthly package.

The problem is that this detection mechanism is too broad - it will scan the full text of the HERMES.md string in the commit history, and cannot distinguish whether this is a real Hermes Agent usage or an unintentional git commit record in the warehouse.

Impact and Key Timeline

Anthropic's response

Practical impact on Claude Code users

1. Silent overage billing: The error message is just "You're out of extra usage", and there is no mention of git commit history as the reason.
2. Extremely high randomness: Triggered in any project, at any time, as long as the commit message HERMES.md appears
3. Plan quota is empty: Max package users find that their monthly quota is still there, but their requests go through the additional billing channel
4. Affects non-Hermes users: This bug does not affect users who actually use Hermes Agent (they should have been charged extra), but only accidentally hurts ordinary users.

Guide to Preventing Pitfalls: 4 Tips from Claude Code Users

1. Check the extra usage bill regularly: Claude Code’s Plan Quota and Extra Usage are displayed independently. If Extra Usage is consumed abnormally, check whether there is an abnormal string in the git repository.
2. Create an orphan branch as a temporary solution: If you encounter this problem, git checkout --orphan clean-branch can skip the history
3. Consider using local models instead: For content production tasks, local-friendly models such as DeepSeek V4 can be used instead of Claude API
4. Focus on third-party Agent alternatives: Claude Code’s billing policy is being tightened, and tools such as OpenClaw and Hermes Agent have been directed to additional billing channels

Related extended information

• GitHub Issue #53262（）
• Hacker News （973 points, 410 comments）
• Consumer Rights Wiki

Tool entry (trigger tool floating card)

The following terms naturally appear in the text, and the platform side will match the maintained tools library: Claude, Claude Code, DeepSeek, Hermes Agent, OpenClaw

Internal link guidance

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• Looking for a replacement for Claude? See the guide: DeepSeek V4 vs Claude Code: 90% Cheaper, Same Quality