Disable Claude Code Billing Header | Generated by AI

Home 2026.03

Question: What does "CLAUDE_CODE_ATTRIBUTION_HEADER": "0" mean in Claude Code’s settings.json?

Answer:Question: What does "CLAUDE_CODE_ATTRIBUTION_HEADER": "0" mean in Claude Code’s settings.json?

Answer:

What CLAUDE_CODE_ATTRIBUTION_HEADER Actually Is

This is an undocumented but real environment variable that controls whether Claude Code sends a special billing/tracking header called x-anthropic-billing-header with every API request.

What the Header Looks Like

Starting with Claude Code version 2.1.36, Claude Code sends a special header that changes with every request. It looks like:

x-anthropic-billing-header: cc_version=xxxx; cc_entrypoint=cli; cch=xxxx;...

What the Header Is For

By default, Claude Code sends this billing attribution header — x-anthropic-billing-header — with every single request. When you’re hitting Anthropic’s actual API, this makes sense: they need to track usage. But when you’re pointing Claude Code at a local model or a relay proxy, that header still goes out, and your server has to process it — overhead on every request, for zero benefit.

What Setting It to "0" Does

When CLAUDE_CODE_ATTRIBUTION_HEADER is set to 0 in the env, Claude Code stops sending this header.

Why This Matters for Your PinCC Setup

This is directly relevant to your situation. The x-anthropic-billing-header sent by Claude Code contains values that change with every request (like a session hash cch=xxxx). This causes two problems when using a relay:

  1. Breaks prompt caching — because the header changes every request, the relay/Anthropic backend sees each request as unique and cannot reuse the cache, making responses slower and more expensive.
  2. May trigger client verification checks — the relay may inspect this header as part of its “is this really Claude Code?” check. A malformed or unexpected value could contribute to the 503 only allows Claude Code clients error.

How to Set It in settings.json

Place it inside the env block:

{
  "env": {
    "CLAUDE_CODE_ATTRIBUTION_HEADER": "0"
  }
}

This is the correct way to set environment variables persistently in Claude Code’s settings.json, rather than using shell exports.

Summary Table

Value Behaviour
Not set (default) Claude Code sends x-anthropic-billing-header with every request (changes per-request)
"0" Claude Code suppresses the header entirely — no billing attribution sent

Recommendation for Your PinCC Setup

Add this to your ~/.claude/settings.json:

{
  "env": {
    "CLAUDE_CODE_ATTRIBUTION_HEADER": "0",
    "ANTHROPIC_BASE_URL": "https://v2-as.pincc.ai",
    "ANTHROPIC_AUTH_TOKEN": "YOUR_PINCC_TOKEN_HERE"
  }
}

This suppresses the dynamic billing header, which helps with both prompt cache stability and avoids sending unexpected header content to the relay. It will not affect Claude Code’s core functionality when used with the official Claude Code CLI pointed at PinCC.

References:

Back Donate