September 25, 2026
Claude Code can give subagents a different model: 4.8 ran instead of Opus 5.5
On Sep 25, 2026, Victor Taelin discovered that Claude Code had routed his subagents to 4.8 instead of Opus 5.5. He left the agents to work on improvements to Bend2 and got a result he considered completely stupid.
Taelin
@victortaelin
I took the day off and left Opus 5.5 to work on improvements to Bend2. The results were AWFUL. Completely stupid. I could not believe how bad the ideas were. Then I asked: “Did you really use Opus 5.5?” It turned out Claude Code had silently routed the subagents to 4.8?
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Now in Claude Code, a subagent model can override a launch parameter or `model` in its frontmatter. The `CLAUDE_CODE_SUBAGENT_MODEL` variable sets only the default model.
You can lock it down. In Claude Code 2.1.257+, the two variables `CLAUDE_CODE_SUBAGENT_MODEL=claude-opus-5-5` and `CLAUDE_CODE_SUBAGENT_MODEL_FORCE=1` pin Opus 5.5 for subagents, teammates, and workflow agents. `/tasks` shows the actual model of a running subagent in versions 2.1.242+.
Rules for forcing model selection appeared in the Claude Code documentation on Sep 24, 2026.
