docs: add GPT 5.2 vs Codex FAQ

docs/help/faq.md

@@ -138,6 +138,7 @@ Quick answers plus deeper troubleshooting for real-world setups (local dev, VPS,
   - [Can I use self-hosted models (llama.cpp, vLLM, Ollama)?](#can-i-use-selfhosted-models-llamacpp-vllm-ollama)
   - [What do Clawd, Flawd, and Krill use for models?](#what-do-clawd-flawd-and-krill-use-for-models)
   - [How do I switch models on the fly (without restarting)?](#how-do-i-switch-models-on-the-fly-without-restarting)
+  - [Can I use GPT 5.2 for daily tasks and Codex 5.2 for coding](#can-i-use-gpt-52-for-daily-tasks-and-codex-52-for-coding)
   - [Why do I see “Model … is not allowed” and then no reply?](#why-do-i-see-model-is-not-allowed-and-then-no-reply)
   - [Why do I see “Unknown model: minimax/MiniMax-M2.1”?](#why-do-i-see-unknown-model-minimaxminimaxm21)
   - [Can I use MiniMax as my default and OpenAI for complex tasks?](#can-i-use-minimax-as-my-default-and-openai-for-complex-tasks)
@@ -1947,6 +1948,16 @@ Re-run `/model` **without** the `@profile` suffix:
 If you want to return to the default, pick it from `/model` (or send `/model <default provider/model>`).
 Use `/model status` to confirm which auth profile is active.
 
+### Can I use GPT 5.2 for daily tasks and Codex 5.2 for coding
+
+Yes. Set one as default and switch as needed:
+
+- **Quick switch (per session):** `/model gpt-5.2` for daily tasks, `/model gpt-5.2-codex` for coding.
+- **Default + switch:** set `agents.defaults.model.primary` to `openai-codex/gpt-5.2`, then switch to `openai-codex/gpt-5.2-codex` when coding (or the other way around).
+- **Sub-agents:** route coding tasks to sub-agents with a different default model.
+
+See [Models](/concepts/models) and [Slash commands](/tools/slash-commands).
+
 ### Why do I see Model is not allowed and then no reply
 
 If `agents.defaults.models` is set, it becomes the **allowlist** for `/model` and any