feat: add xhigh thinking level support for gpt-5.2 models

- Add supportsXhigh() function to ai package for checking xhigh support
- Clamp xhigh to high for OpenAI models that don't support it
- Update coding-agent to use centralized supportsXhigh()
- gpt-5.2, gpt-5.2-codex now show xhigh in thinking selector

Closes #236

packages/coding-agent/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Added
+
+- **xhigh thinking level for gpt-5.2 models**: The thinking level selector and shift+tab cycling now show xhigh option for gpt-5.2 and gpt-5.2-codex models (in addition to gpt-5.1-codex-max). ([#236](https://github.com/badlogic/pi-mono/pull/236) by [@theBucky](https://github.com/theBucky))
+
 ### Fixed
 
 - **Hooks wrap custom tools**: Custom tools are now executed through the hook wrapper, so `tool_call`/`tool_result` hooks can observe, block, and modify custom tool executions (consistent with hook type docs).

packages/coding-agent/src/core/agent-session.ts

@@ -15,7 +15,7 @@
 
 import type { Agent, AgentEvent, AgentState, AppMessage, Attachment, ThinkingLevel } from "@mariozechner/pi-agent-core";
 import type { AssistantMessage, Message, Model, TextContent } from "@mariozechner/pi-ai";
-import { isContextOverflow } from "@mariozechner/pi-ai";
+import { isContextOverflow, supportsXhigh } from "@mariozechner/pi-ai";
 import { getModelsPath } from "../config.js";
 import { type BashResult, executeBash as executeBashCommand } from "./bash-executor.js";
 import { calculateContextTokens, compact, shouldCompact } from "./compaction.js";
@@ -102,9 +102,6 @@ export interface SessionStats {
 // Constants
 // ============================================================================
 
-/** Models that support xhigh thinking level */
-const XHIGH_MODELS = ["gpt-5.1-codex-max", "gpt-5.2", "gpt-5.2-codex"];
-
 /** Standard thinking levels */
 const THINKING_LEVELS: ThinkingLevel[] = ["off", "minimal", "low", "medium", "high"];
 
@@ -670,8 +667,7 @@ export class AgentSession {
 	 * Check if current model supports xhigh thinking level.
 	 */
 	supportsXhighThinking(): boolean {
-		const modelId = this.model?.id || "";
-		return XHIGH_MODELS.some((m) => modelId === m || modelId.endsWith(`/${m}`));
+		return this.model ? supportsXhigh(this.model) : false;
 	}
 
 	/**