[FEATURE]: Configurable thinking mode for session title generation (default to non-thinking) #25456

• I have verified this feature I'm about to request hasn't been suggested before.

Session title generation is a lightweight, insignificant operation — it doesn't warrant using the model's thinking/reasoning capabilities. Using thinking mode for title generation wastes compute, tokens, and adds unnecessary latency with no meaningful benefit to output quality.

Proposed change: Default session title generation to non-thinking when possible, but allow users to opt into thinking if desired via configuration:

{
  "$schema": "https://opencode.ai/config.json",
  "agent": {
    "title": {
      // can be set to "none", "minimal", "low", "medium", "high"
      "thinking": "none"  // default: no thinking for title generation
    }
  }
}

Benefits:

• Reduces token usage and cost on every session start
• Lowers latency for session initialization
• Keeps thinking/reasoning reserved for tasks that actually benefit from it (agent work, code generation, etc.)
• Gives users full control if they prefer reasoning during title gen