fix: clean up Codex thinking level handling

- Remove per-thinking-level model variants (gpt-5.2-codex-high, etc.)
- Remove thinkingLevels from Model type
- Provider clamps reasoning effort internally
- Omit reasoning field when thinking is off

fixes #472

packages/agent/src/agent.ts

@@ -8,7 +8,6 @@ import {
 	type ImageContent,
 	type Message,
 	type Model,
-	type ReasoningEffort,
 	streamSimple,
 	type TextContent,
 } from "@mariozechner/pi-ai";
@@ -276,8 +275,7 @@ export class Agent {
 		this._state.streamMessage = null;
 		this._state.error = undefined;
 
-		const reasoning: ReasoningEffort | undefined =
+		const reasoning = this._state.thinkingLevel === "off" ? undefined : this._state.thinkingLevel;
-			this._state.thinkingLevel === "off" ? undefined : (this._state.thinkingLevel as ReasoningEffort);
 
 		const context: AgentContext = {
 			systemPrompt: this._state.systemPrompt,

packages/ai/CHANGELOG.md

@@ -2,11 +2,19 @@
 
 ## [Unreleased]
 
+### Breaking Changes
+
+- OpenAI Codex models no longer have per-thinking-level variants (e.g., `gpt-5.2-codex-high`). Use the base model ID and set thinking level separately. The Codex provider clamps reasoning effort to what each model supports internally. (initial implementation by [@ben-vargas](https://github.com/ben-vargas) in [#472](https://github.com/badlogic/pi-mono/pull/472))
+
 ### Added
 
 - Headless OAuth support for all callback-server providers (Google Gemini CLI, Antigravity, OpenAI Codex): paste redirect URL when browser callback is unreachable ([#428](https://github.com/badlogic/pi-mono/pull/428) by [@ben-vargas](https://github.com/ben-vargas), [#468](https://github.com/badlogic/pi-mono/pull/468) by [@crcatala](https://github.com/crcatala))
 - Cancellable GitHub Copilot device code polling via AbortSignal
 
+### Fixed
+
+- Codex requests now omit the `reasoning` field entirely when thinking is off, letting the backend use its default instead of forcing a value. ([#472](https://github.com/badlogic/pi-mono/pull/472))
+
 ## [0.36.0] - 2026-01-05
 
 ### Added

packages/ai/scripts/generate-models.ts

@@ -454,7 +454,6 @@ async function generateModels() {
 			provider: "openai-codex",
 			baseUrl: CODEX_BASE_URL,
 			reasoning: true,
-			thinkingLevels: ["low", "medium", "high", "xhigh"],
 			input: ["text", "image"],
 			cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
 			contextWindow: CODEX_CONTEXT,
@@ -479,7 +478,6 @@ async function generateModels() {
 			provider: "openai-codex",
 			baseUrl: CODEX_BASE_URL,
 			reasoning: true,
-			thinkingLevels: ["low", "medium", "high", "xhigh"],
 			input: ["text", "image"],
 			cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
 			contextWindow: CODEX_CONTEXT,
@@ -492,7 +490,6 @@ async function generateModels() {
 			provider: "openai-codex",
 			baseUrl: CODEX_BASE_URL,
 			reasoning: true,
-			thinkingLevels: ["low", "medium", "high"],
 			input: ["text", "image"],
 			cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
 			contextWindow: CODEX_CONTEXT,
@@ -505,7 +502,6 @@ async function generateModels() {
 			provider: "openai-codex",
 			baseUrl: CODEX_BASE_URL,
 			reasoning: true,
-			thinkingLevels: ["medium", "high"],
 			input: ["text", "image"],
 			cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
 			contextWindow: CODEX_CONTEXT,
@@ -518,7 +514,6 @@ async function generateModels() {
 			provider: "openai-codex",
 			baseUrl: CODEX_BASE_URL,
 			reasoning: true,
-			thinkingLevels: ["medium", "high"],
 			input: ["text", "image"],
 			cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
 			contextWindow: CODEX_CONTEXT,
@@ -531,7 +526,6 @@ async function generateModels() {
 			provider: "openai-codex",
 			baseUrl: CODEX_BASE_URL,
 			reasoning: true,
-			thinkingLevels: ["medium", "high"],
 			input: ["text", "image"],
 			cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
 			contextWindow: CODEX_CONTEXT,
@@ -544,7 +538,6 @@ async function generateModels() {
 			provider: "openai-codex",
 			baseUrl: CODEX_BASE_URL,
 			reasoning: true,
-			thinkingLevels: ["low", "medium", "high"],
 			input: ["text", "image"],
 			cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
 			contextWindow: CODEX_CONTEXT,
@@ -999,9 +992,6 @@ export const MODELS = {
 `;
 			}
 			output += `\t\t\treasoning: ${model.reasoning},\n`;
-			if (model.thinkingLevels) {
-				output += `\t\t\tthinkingLevels: ${JSON.stringify(model.thinkingLevels)},\n`;
-			}
 			output += `\t\t\tinput: [${model.input.map(i => `"${i}"`).join(", ")}],\n`;
 			output += `\t\t\tcost: {\n`;
 			output += `\t\t\t\tinput: ${model.cost.input},\n`;

packages/ai/src/models.generated.ts

@@ -2781,7 +2781,6 @@ export const MODELS = {
 			provider: "openai-codex",
 			baseUrl: "https://chatgpt.com/backend-api",
 			reasoning: true,
-			thinkingLevels: ["medium","high"],
 			input: ["text", "image"],
 			cost: {
 				input: 0,
@@ -2816,7 +2815,6 @@ export const MODELS = {
 			provider: "openai-codex",
 			baseUrl: "https://chatgpt.com/backend-api",
 			reasoning: true,
-			thinkingLevels: ["low","medium","high"],
 			input: ["text", "image"],
 			cost: {
 				input: 0,
@@ -2834,7 +2832,6 @@ export const MODELS = {
 			provider: "openai-codex",
 			baseUrl: "https://chatgpt.com/backend-api",
 			reasoning: true,
-			thinkingLevels: ["medium","high"],
 			input: ["text", "image"],
 			cost: {
 				input: 0,
@@ -2920,7 +2917,6 @@ export const MODELS = {
 			provider: "openai-codex",
 			baseUrl: "https://chatgpt.com/backend-api",
 			reasoning: true,
-			thinkingLevels: ["low","medium","high"],
 			input: ["text", "image"],
 			cost: {
 				input: 0,
@@ -2938,7 +2934,6 @@ export const MODELS = {
 			provider: "openai-codex",
 			baseUrl: "https://chatgpt.com/backend-api",
 			reasoning: true,
-			thinkingLevels: ["low","medium","high","xhigh"],
 			input: ["text", "image"],
 			cost: {
 				input: 0,
@@ -2956,7 +2951,6 @@ export const MODELS = {
 			provider: "openai-codex",
 			baseUrl: "https://chatgpt.com/backend-api",
 			reasoning: true,
-			thinkingLevels: ["medium","high"],
 			input: ["text", "image"],
 			cost: {
 				input: 0,
@@ -2991,7 +2985,6 @@ export const MODELS = {
 			provider: "openai-codex",
 			baseUrl: "https://chatgpt.com/backend-api",
 			reasoning: true,
-			thinkingLevels: ["low","medium","high","xhigh"],
 			input: ["text", "image"],
 			cost: {
 				input: 0,
@@ -4056,7 +4049,7 @@ export const MODELS = {
 				cacheWrite: 0,
 			},
 			contextWindow: 256000,
-			maxTokens: 32768,
+			maxTokens: 128000,
 		} satisfies Model<"openai-completions">,
 		"meta-llama/llama-3-70b-instruct": {
 			id: "meta-llama/llama-3-70b-instruct",
@@ -6676,6 +6669,23 @@ export const MODELS = {
 			contextWindow: 163840,
 			maxTokens: 65536,
 		} satisfies Model<"openai-completions">,
+		"tngtech/tng-r1t-chimera:free": {
+			id: "tngtech/tng-r1t-chimera:free",
+			name: "TNG: R1T Chimera (free)",
+			api: "openai-completions",
+			provider: "openrouter",
+			baseUrl: "https://openrouter.ai/api/v1",
+			reasoning: true,
+			input: ["text"],
+			cost: {
+				input: 0,
+				output: 0,
+				cacheRead: 0,
+				cacheWrite: 0,
+			},
+			contextWindow: 163840,
+			maxTokens: 65536,
+		} satisfies Model<"openai-completions">,
 		"x-ai/grok-3": {
 			id: "x-ai/grok-3",
 			name: "xAI: Grok 3",

packages/ai/src/models.ts

@@ -1,50 +1,13 @@
 import { MODELS } from "./models.generated.js";
-import type { Api, KnownProvider, Model, ReasoningEffort, Usage } from "./types.js";
+import type { Api, KnownProvider, Model, Usage } from "./types.js";
 
 const modelRegistry: Map<string, Map<string, Model<Api>>> = new Map();
 
-const CODEX_THINKING_SUFFIXES = ["-none", "-minimal", "-low", "-medium", "-high", "-xhigh"];
-const CODEX_THINKING_LEVELS: Record<string, ReasoningEffort[]> = {
-	"gpt-5.2-codex": ["low", "medium", "high", "xhigh"],
-	"gpt-5.1-codex-max": ["low", "medium", "high", "xhigh"],
-	"gpt-5.1-codex": ["low", "medium", "high"],
-	"gpt-5.1-codex-mini": ["medium", "high"],
-	"codex-mini-latest": ["medium", "high"],
-	"gpt-5-codex-mini": ["medium", "high"],
-	"gpt-5-codex": ["low", "medium", "high"],
-};
-
-function isCodexThinkingVariant(modelId: string): boolean {
-	const normalized = modelId.toLowerCase();
-	return CODEX_THINKING_SUFFIXES.some((suffix) => normalized.endsWith(suffix));
-}
-
-function normalizeCodexModelId(modelId: string): string {
-	const normalized = modelId.toLowerCase();
-	for (const suffix of CODEX_THINKING_SUFFIXES) {
-		if (normalized.endsWith(suffix)) {
-			return modelId.slice(0, modelId.length - suffix.length);
-		}
-	}
-	return modelId;
-}
-
-function applyCodexThinkingLevels<TApi extends Api>(model: Model<TApi>): Model<TApi> {
-	if (model.provider !== "openai-codex") return model;
-	const thinkingLevels = CODEX_THINKING_LEVELS[model.id];
-	if (!thinkingLevels) return model;
-	return { ...model, thinkingLevels };
-}
-
 // Initialize registry from MODELS on module load
 for (const [provider, models] of Object.entries(MODELS)) {
 	const providerModels = new Map<string, Model<Api>>();
 	for (const [id, model] of Object.entries(models)) {
-		const typedModel = model as Model<Api>;
+		providerModels.set(id, model as Model<Api>);
-		if (provider === "openai-codex" && isCodexThinkingVariant(typedModel.id)) {
-			continue;
-		}
-		providerModels.set(id, applyCodexThinkingLevels(typedModel));
 	}
 	modelRegistry.set(provider, providerModels);
 }
@@ -59,16 +22,7 @@ export function getModel<TProvider extends KnownProvider, TModelId extends keyof
 	modelId: TModelId,
 ): Model<ModelApi<TProvider, TModelId>> {
 	const providerModels = modelRegistry.get(provider);
-	const direct = providerModels?.get(modelId as string);
+	return providerModels?.get(modelId as string) as Model<ModelApi<TProvider, TModelId>>;
-	if (direct) return direct as Model<ModelApi<TProvider, TModelId>>;
-	if (provider === "openai-codex") {
-		const normalized = normalizeCodexModelId(modelId as string);
-		const normalizedModel = providerModels?.get(normalized);
-		if (normalizedModel) {
-			return normalizedModel as Model<ModelApi<TProvider, TModelId>>;
-		}
-	}
-	return direct as unknown as Model<ModelApi<TProvider, TModelId>>;
 }
 
 export function getProviders(): KnownProvider[] {
@@ -96,12 +50,9 @@ const XHIGH_MODELS = new Set(["gpt-5.1-codex-max", "gpt-5.2", "gpt-5.2-codex"]);
 
 /**
  * Check if a model supports xhigh thinking level.
- * Currently only certain OpenAI models support this.
+ * Currently only certain OpenAI Codex models support this.
  */
 export function supportsXhigh<TApi extends Api>(model: Model<TApi>): boolean {
-	if (model.thinkingLevels) {
-		return model.thinkingLevels.includes("xhigh");
-	}
 	return XHIGH_MODELS.has(model.id);
 }
 

packages/ai/src/stream.ts

@@ -21,8 +21,8 @@ import type {
 	KnownProvider,
 	Model,
 	OptionsForApi,
-	ReasoningEffort,
 	SimpleStreamOptions,
+	ThinkingLevel,
 } from "./types.js";
 
 const VERTEX_ADC_CREDENTIALS_PATH = join(homedir(), ".config", "gcloud", "application_default_credentials.json");
@@ -180,7 +180,7 @@ function mapOptionsForApi<TApi extends Api>(
 	};
 
 	// Helper to clamp xhigh to high for providers that don't support it
-	const clampReasoning = (effort: ReasoningEffort | undefined) => (effort === "xhigh" ? "high" : effort);
+	const clampReasoning = (effort: ThinkingLevel | undefined) => (effort === "xhigh" ? "high" : effort);
 
 	switch (model.api) {
 		case "anthropic-messages": {
@@ -286,7 +286,7 @@ function mapOptionsForApi<TApi extends Api>(
 			// Models using thinkingBudget (Gemini 2.x, Claude via Antigravity)
 			// Claude requires max_tokens > thinking.budget_tokens
 			// So we need to ensure maxTokens accounts for both thinking and output
-			const budgets: Record<ClampedReasoningEffort, number> = {
+			const budgets: Record<ClampedThinkingLevel, number> = {
 				minimal: 1024,
 				low: 2048,
 				medium: 8192,
@@ -350,7 +350,7 @@ function mapOptionsForApi<TApi extends Api>(
 	}
 }
 
-type ClampedReasoningEffort = Exclude<ReasoningEffort, "xhigh">;
+type ClampedThinkingLevel = Exclude<ThinkingLevel, "xhigh">;
 
 function isGemini3ProModel(model: Model<"google-generative-ai">): boolean {
 	// Covers gemini-3-pro, gemini-3-pro-preview, and possible other prefixed ids in the future
@@ -363,7 +363,7 @@ function isGemini3FlashModel(model: Model<"google-generative-ai">): boolean {
 }
 
 function getGemini3ThinkingLevel(
-	effort: ClampedReasoningEffort,
+	effort: ClampedThinkingLevel,
 	model: Model<"google-generative-ai">,
 ): GoogleThinkingLevel {
 	if (isGemini3ProModel(model)) {
@@ -390,7 +390,7 @@ function getGemini3ThinkingLevel(
 	}
 }
 
-function getGeminiCliThinkingLevel(effort: ClampedReasoningEffort, modelId: string): GoogleThinkingLevel {
+function getGeminiCliThinkingLevel(effort: ClampedThinkingLevel, modelId: string): GoogleThinkingLevel {
 	if (modelId.includes("3-pro")) {
 		// Gemini 3 Pro only supports LOW/HIGH (for now)
 		switch (effort) {
@@ -415,10 +415,10 @@ function getGeminiCliThinkingLevel(effort: ClampedReasoningEffort, modelId: stri
 	}
 }
 
-function getGoogleBudget(model: Model<"google-generative-ai">, effort: ClampedReasoningEffort): number {
+function getGoogleBudget(model: Model<"google-generative-ai">, effort: ClampedThinkingLevel): number {
 	// See https://ai.google.dev/gemini-api/docs/thinking#set-budget
 	if (model.id.includes("2.5-pro")) {
-		const budgets: Record<ClampedReasoningEffort, number> = {
+		const budgets: Record<ClampedThinkingLevel, number> = {
 			minimal: 128,
 			low: 2048,
 			medium: 8192,
@@ -429,7 +429,7 @@ function getGoogleBudget(model: Model<"google-generative-ai">, effort: ClampedRe
 
 	if (model.id.includes("2.5-flash")) {
 		// Covers 2.5-flash-lite as well
-		const budgets: Record<ClampedReasoningEffort, number> = {
+		const budgets: Record<ClampedThinkingLevel, number> = {
 			minimal: 128,
 			low: 2048,
 			medium: 8192,

packages/ai/src/types.ts

@@ -56,7 +56,7 @@ export type KnownProvider =
 	| "mistral";
 export type Provider = KnownProvider | string;
 
-export type ReasoningEffort = "minimal" | "low" | "medium" | "high" | "xhigh";
+export type ThinkingLevel = "minimal" | "low" | "medium" | "high" | "xhigh";
 
 // Base options all providers share
 export interface StreamOptions {
@@ -68,7 +68,7 @@ export interface StreamOptions {
 
 // Unified options with reasoning passed to streamSimple() and completeSimple()
 export interface SimpleStreamOptions extends StreamOptions {
-	reasoning?: ReasoningEffort;
+	reasoning?: ThinkingLevel;
 }
 
 // Generic StreamFunction with typed options
@@ -210,8 +210,6 @@ export interface Model<TApi extends Api> {
 	provider: Provider;
 	baseUrl: string;
 	reasoning: boolean;
-	/** Supported reasoning levels for this model (excluding "off"). */
-	thinkingLevels?: ReasoningEffort[];
 	input: ("text" | "image")[];
 	cost: {
 		input: number; // $/million tokens

packages/coding-agent/CHANGELOG.md

@@ -11,10 +11,7 @@
 
 - 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)
-
+- OpenAI Codex clean-up: removed per-thinking-level model variants, thinking level is now set separately and the provider clamps to what each model supports internally (initial implementation in [#472](https://github.com/badlogic/pi-mono/pull/472) by [@ben-vargas](https://github.com/ben-vargas))
-### Changed
-
-- Thinking level availability now reflects per-model supported reasoning levels.
 
 ### Fixed
 
@@ -24,7 +21,6 @@
 - 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/src/core/agent-session.ts

@@ -1007,16 +1007,10 @@ export class AgentSession {
 
 	/**
 	 * Get available thinking levels for current model.
+	 * The provider will clamp to what the specific model supports internally.
 	 */
 	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;
 	}
 

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

@@ -18,16 +18,6 @@ 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()),
@@ -50,7 +40,6 @@ 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(),
@@ -118,14 +107,6 @@ 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.
  */
@@ -349,7 +330,6 @@ 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,
@@ -383,15 +363,7 @@ export class ModelRegistry {
 	 * Find a model by provider and ID.
 	 */
 	find(provider: string, modelId: string): Model<Api> | undefined {
-		const exact = this.models.find((m) => m.provider === provider && m.id === modelId);
+		return 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

@@ -102,18 +102,6 @@ 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).
@@ -134,14 +122,6 @@ 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) {