fix: codex thinking handling

packages/coding-agent/CHANGELOG.md

@@ -12,6 +12,10 @@
 - OAuth login UI now uses dedicated dialog component with consistent borders
 - Assume truecolor support for all terminals except `dumb`, empty, or `linux` (fixes colors over SSH)
 
+### Changed
+
+- Thinking level availability now reflects per-model supported reasoning levels.
+
 ### Fixed
 
 - Managed binaries (`fd`, `rg`) now stored in `~/.pi/agent/bin/` instead of `tools/`, eliminating false deprecation warnings ([#470](https://github.com/badlogic/pi-mono/pull/470) by [@mcinteerj](https://github.com/mcinteerj))
@@ -20,6 +24,7 @@
 - Migration warnings now ignore `fd.exe` and `rg.exe` in `tools/` on Windows ([#458](https://github.com/badlogic/pi-mono/pull/458) by [@carlosgtrz](https://github.com/carlosgtrz))
 - CI: add `examples/extensions/with-deps` to workspaces to fix typecheck ([#467](https://github.com/badlogic/pi-mono/pull/467) by [@aliou](https://github.com/aliou))
 - SDK: passing `extensions: []` now disables extension discovery as documented ([#465](https://github.com/badlogic/pi-mono/pull/465) by [@aliou](https://github.com/aliou))
+- Legacy Codex model IDs with thinking suffixes resolve to their base models.
 
 ## [0.36.0] - 2026-01-05
 

packages/coding-agent/package.json

@@ -54,6 +54,7 @@
 	},
 	"devDependencies": {
 		"@types/diff": "^7.0.2",
+		"@types/ms": "^2.1.0",
 		"@types/node": "^24.3.0",
 		"@types/proper-lockfile": "^4.1.4",
 		"typescript": "^5.7.3",

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

@@ -978,16 +978,12 @@ export class AgentSession {
 
 	/**
 	 * Set thinking level.
-	 * Clamps to model capabilities: "off" if no reasoning, "high" if xhigh unsupported.
+	 * Clamps to model capabilities based on available thinking levels.
 	 * Saves to session and settings.
 	 */
 	setThinkingLevel(level: ThinkingLevel): void {
-		let effectiveLevel = level;
-		if (!this.supportsThinking()) {
-			effectiveLevel = "off";
-		} else if (level === "xhigh" && !this.supportsXhighThinking()) {
-			effectiveLevel = "high";
-		}
+		const availableLevels = this.getAvailableThinkingLevels();
+		const effectiveLevel = availableLevels.includes(level) ? level : this._clampThinkingLevel(level, availableLevels);
 		this.agent.setThinkingLevel(effectiveLevel);
 		this.sessionManager.appendThinkingLevelChange(effectiveLevel);
 		this.settingsManager.setDefaultThinkingLevel(effectiveLevel);
@@ -1013,6 +1009,14 @@ export class AgentSession {
 	 * Get available thinking levels for current model.
 	 */
 	getAvailableThinkingLevels(): ThinkingLevel[] {
+		if (!this.supportsThinking()) return ["off"];
+
+		const modelLevels = this.model?.thinkingLevels;
+		if (modelLevels && modelLevels.length > 0) {
+			const withOff: ThinkingLevel[] = ["off", ...modelLevels];
+			return THINKING_LEVELS_WITH_XHIGH.filter((level) => withOff.includes(level));
+		}
+
 		return this.supportsXhighThinking() ? THINKING_LEVELS_WITH_XHIGH : THINKING_LEVELS;
 	}
 
@@ -1030,6 +1034,24 @@ export class AgentSession {
 		return !!this.model?.reasoning;
 	}
 
+	private _clampThinkingLevel(level: ThinkingLevel, availableLevels: ThinkingLevel[]): ThinkingLevel {
+		const ordered = THINKING_LEVELS_WITH_XHIGH;
+		const available = new Set(availableLevels);
+		const requestedIndex = ordered.indexOf(level);
+		if (requestedIndex === -1) {
+			return availableLevels[0] ?? "off";
+		}
+		for (let i = requestedIndex; i < ordered.length; i++) {
+			const candidate = ordered[i];
+			if (available.has(candidate)) return candidate;
+		}
+		for (let i = requestedIndex - 1; i >= 0; i--) {
+			const candidate = ordered[i];
+			if (available.has(candidate)) return candidate;
+		}
+		return availableLevels[0] ?? "off";
+	}
+
 	// =========================================================================
 	// Queue Mode Management
 	// =========================================================================

packages/coding-agent/src/core/model-registry.ts

@@ -18,6 +18,16 @@ import type { AuthStorage } from "./auth-storage.js";
 
 const Ajv = (AjvModule as any).default || AjvModule;
 
+const ThinkingLevelsSchema = Type.Array(
+	Type.Union([
+		Type.Literal("minimal"),
+		Type.Literal("low"),
+		Type.Literal("medium"),
+		Type.Literal("high"),
+		Type.Literal("xhigh"),
+	]),
+);
+
 // Schema for OpenAI compatibility settings
 const OpenAICompatSchema = Type.Object({
 	supportsStore: Type.Optional(Type.Boolean()),
@@ -40,6 +50,7 @@ const ModelDefinitionSchema = Type.Object({
 		]),
 	),
 	reasoning: Type.Boolean(),
+	thinkingLevels: Type.Optional(ThinkingLevelsSchema),
 	input: Type.Array(Type.Union([Type.Literal("text"), Type.Literal("image")])),
 	cost: Type.Object({
 		input: Type.Number(),
@@ -107,6 +118,14 @@ function resolveApiKeyConfig(keyConfig: string): string | undefined {
 	return keyConfig;
 }
 
+function normalizeCodexModelId(modelId: string): string {
+	const suffixes = ["-none", "-minimal", "-low", "-medium", "-high", "-xhigh"];
+	const normalized = modelId.toLowerCase();
+	const matchedSuffix = suffixes.find((suffix) => normalized.endsWith(suffix));
+	if (!matchedSuffix) return modelId;
+	return modelId.slice(0, modelId.length - matchedSuffix.length);
+}
+
 /**
  * Model registry - loads and manages models, resolves API keys via AuthStorage.
  */
@@ -330,6 +349,7 @@ export class ModelRegistry {
 					provider: providerName,
 					baseUrl: providerConfig.baseUrl!,
 					reasoning: modelDef.reasoning,
+					thinkingLevels: modelDef.thinkingLevels,
 					input: modelDef.input as ("text" | "image")[],
 					cost: modelDef.cost,
 					contextWindow: modelDef.contextWindow,
@@ -363,7 +383,15 @@ export class ModelRegistry {
 	 * Find a model by provider and ID.
 	 */
 	find(provider: string, modelId: string): Model<Api> | undefined {
-		return this.models.find((m) => m.provider === provider && m.id === modelId) ?? undefined;
+		const exact = this.models.find((m) => m.provider === provider && m.id === modelId);
+		if (exact) return exact;
+		if (provider === "openai-codex") {
+			const normalized = normalizeCodexModelId(modelId);
+			if (normalized !== modelId) {
+				return this.models.find((m) => m.provider === provider && m.id === normalized) ?? undefined;
+			}
+		}
+		return undefined;
 	}
 
 	/**

packages/coding-agent/src/core/model-resolver.ts

@@ -102,6 +102,18 @@ export interface ParsedModelResult {
 	warning: string | undefined;
 }
 
+const THINKING_SUFFIXES = ["-none", "-minimal", "-low", "-medium", "-high", "-xhigh"];
+
+function stripThinkingSuffix(pattern: string): string {
+	const normalized = pattern.toLowerCase();
+	for (const suffix of THINKING_SUFFIXES) {
+		if (normalized.endsWith(suffix)) {
+			return pattern.slice(0, pattern.length - suffix.length);
+		}
+	}
+	return pattern;
+}
+
 /**
  * Parse a pattern to extract model and thinking level.
  * Handles models with colons in their IDs (e.g., OpenRouter's :exacto suffix).
@@ -122,6 +134,14 @@ export function parseModelPattern(pattern: string, availableModels: Model<Api>[]
 		return { model: exactMatch, thinkingLevel: "off", warning: undefined };
 	}
 
+	const normalizedPattern = stripThinkingSuffix(pattern);
+	if (normalizedPattern !== pattern) {
+		const normalizedMatch = tryMatchModel(normalizedPattern, availableModels);
+		if (normalizedMatch) {
+			return { model: normalizedMatch, thinkingLevel: "off", warning: undefined };
+		}
+	}
+
 	// No match - try splitting on last colon if present
 	const lastColonIndex = pattern.lastIndexOf(":");
 	if (lastColonIndex === -1) {