"model" setting in settings.json not applied on session start

Bug Report

Setting \"model\" in ~/.claude/settings.json is not applied on session start.

Steps to Reproduce

1. Add "model": "opusplan" to ~/.claude/settings.json
2. Start a new Claude Code session
3. Ask "what model are you?"

Expected Behavior

Claude should start on Opus 4.6 (in plan mode) or Sonnet 4.6 (otherwise), as per the opusplan routing.

Actual Behavior

Claude reports running on Sonnet 4.6 regardless of plan mode, as if the model setting was not read.

Workaround

Running /model opusplan at runtime works correctly.

Config

{
  "model": "opusplan"
}

Environment

• Platform: macOS (Darwin 24.6.0)
• Shell: zsh