> ## Documentation Index
> Fetch the complete documentation index at: https://docs.apiyi.com/llms.txt
> Use this file to discover all available pages before exploring further.

# New FAQ: Why Logs Show Haiku When Claude Code Is Set to Opus

> A new FAQ explains that Claude Code offloads background tasks like session titles and some subagents to Haiku to save cost, so seeing both models in your logs is normal, and shows how to force everything onto Opus.

**2026/10/16 10:50 (UTC+8)** · Docs Update · Anthropic

📚 **New FAQ: [Why Do My Logs Show Haiku When Claude Code Is Set to Opus?](/en/faq/claude-code-haiku-background-model)**

This is Claude Code's own cost-saving behavior: the main conversation uses the Opus model you configured, while background tasks such as session titles and topic detection, plus built-in subagents like Explore, default to a small model such as `claude-haiku-4-5-20251001`. Those calls are billed at Haiku pricing — the gateway is not swapping your model.

To run everything on Opus, point `ANTHROPIC_DEFAULT_HAIKU_MODEL`, `CLAUDE_CODE_SUBAGENT_MODEL` and related variables at `claude-opus-5-5` in `~/.claude/settings.json`; costs will rise accordingly. The FAQ is listed under Use Cases → Claude Code.

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