docs: clarify xhigh reasoning effort on gpt-5.2 (#7911)

## Changes
- Update config docs and example config comments to state that "xhigh"
is supported on gpt-5.2 as well as gpt-5.1-codex-max
- Adjust the FAQ model-support section to reflect broader xhigh
availability

docs/config.md

@@ -195,7 +195,7 @@ If the selected model is known to support reasoning (for example: `o3`, `o4-mini
 - `"low"`
 - `"medium"` (default)
 - `"high"`
-- `"xhigh"` (available only on `gpt-5.1-codex-max`)
+- `"xhigh"` (available on `gpt-5.1-codex-max` and `gpt-5.2`)
 
 Note: to minimize reasoning, choose `"minimal"`.
 

docs/example-config.md

@@ -37,7 +37,7 @@ model_provider = "openai"
 # Reasoning & Verbosity (Responses API capable models)
 ################################################################################
 
-# Reasoning effort: minimal | low | medium | high | xhigh (default: medium; xhigh only on gpt-5.1-codex-max)
+# Reasoning effort: minimal | low | medium | high | xhigh (default: medium; xhigh on gpt-5.1-codex-max and gpt-5.2)
 model_reasoning_effort = "medium"
 
 # Reasoning summary: auto | concise | detailed | none (default: auto)

docs/faq.md

@@ -8,7 +8,7 @@ In 2021, OpenAI released Codex, an AI system designed to generate code from natu
 
 ### Which models are supported?
 
-We recommend using Codex with GPT-5.1 Codex Max, our best coding model. The default reasoning level is medium, and you can upgrade to high or xhigh (Codex Max only) for complex tasks with the `/model` command.
+We recommend using Codex with GPT-5.1 Codex Max, our best coding model. The default reasoning level is medium, and you can upgrade to high or xhigh (where supported, e.g. `gpt-5.1-codex-max` and `gpt-5.2`) for complex tasks with the `/model` command.
 
 You can also use older models by using API-based auth and launching codex with the `--model` flag.