diff --git a/packages/ai/CHANGELOG.md b/packages/ai/CHANGELOG.md
index ed94d524..48e5af4f 100644
--- a/packages/ai/CHANGELOG.md
+++ b/packages/ai/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Fixed
+
+- Fixed OpenAI Codex OAuth model list (removed aliases), aligned context window/maxTokens with observed backend limits, and refined reasoning effort clamping.
+
 ## [0.37.8] - 2026-01-07
 
 ## [0.37.7] - 2026-01-07
diff --git a/packages/ai/scripts/generate-models.ts b/packages/ai/scripts/generate-models.ts
index 4f52d8a2..431c8678 100644
--- a/packages/ai/scripts/generate-models.ts
+++ b/packages/ai/scripts/generate-models.ts
@@ -443,37 +443,16 @@ async function generateModels() {
 	}
 
 	// OpenAI Codex (ChatGPT OAuth) models
+	// NOTE: These are not fetched from models.dev; we keep a small, explicit list to avoid aliases.
+	// Context window is based on observed server limits (400s above ~272k), not marketing numbers.
 	const CODEX_BASE_URL = "https://chatgpt.com/backend-api";
-	const CODEX_CONTEXT = 400000;
-	const CODEX_MAX_TOKENS = 128000;
+	const CODEX_CONTEXT = 272000;
+	// Use the same max output token budget as Codex CLI.
+	const CODEX_MAX_TOKENS = 10000;
 	const codexModels: Model<"openai-codex-responses">[] = [
 		{
-			id: "gpt-5.2-codex",
-			name: "GPT-5.2 Codex",
-			api: "openai-codex-responses",
-			provider: "openai-codex",
-			baseUrl: CODEX_BASE_URL,
-			reasoning: true,
-			input: ["text", "image"],
-			cost: { input: 1.75, output: 14, cacheRead: 0.175, cacheWrite: 0 },
-			contextWindow: CODEX_CONTEXT,
-			maxTokens: CODEX_MAX_TOKENS,
-		},
-		{
-			id: "gpt-5.2",
-			name: "GPT-5.2",
-			api: "openai-codex-responses",
-			provider: "openai-codex",
-			baseUrl: CODEX_BASE_URL,
-			reasoning: true,
-			input: ["text", "image"],
-			cost: { input: 1.75, output: 14, cacheRead: 0.175, cacheWrite: 0 },
-			contextWindow: CODEX_CONTEXT,
-			maxTokens: CODEX_MAX_TOKENS,
-		},
-		{
-			id: "gpt-5.1-codex-max",
-			name: "GPT-5.1 Codex Max",
+			id: "gpt-5.1",
+			name: "GPT-5.1",
 			api: "openai-codex-responses",
 			provider: "openai-codex",
 			baseUrl: CODEX_BASE_URL,
@@ -484,8 +463,8 @@ async function generateModels() {
 			maxTokens: CODEX_MAX_TOKENS,
 		},
 		{
-			id: "gpt-5.1-codex",
-			name: "GPT-5.1 Codex",
+			id: "gpt-5.1-codex-max",
+			name: "GPT-5.1 Codex Max",
 			api: "openai-codex-responses",
 			provider: "openai-codex",
 			baseUrl: CODEX_BASE_URL,
@@ -508,98 +487,26 @@ async function generateModels() {
 			maxTokens: CODEX_MAX_TOKENS,
 		},
 		{
-			id: "codex-mini-latest",
-			name: "Codex Mini Latest",
+			id: "gpt-5.2",
+			name: "GPT-5.2",
 			api: "openai-codex-responses",
 			provider: "openai-codex",
 			baseUrl: CODEX_BASE_URL,
 			reasoning: true,
 			input: ["text", "image"],
-			cost: { input: 1.5, output: 6, cacheRead: 0.375, cacheWrite: 0 },
+			cost: { input: 1.75, output: 14, cacheRead: 0.175, cacheWrite: 0 },
 			contextWindow: CODEX_CONTEXT,
 			maxTokens: CODEX_MAX_TOKENS,
 		},
 		{
-			id: "gpt-5-codex-mini",
-			name: "gpt-5-codex-mini",
+			id: "gpt-5.2-codex",
+			name: "GPT-5.2 Codex",
 			api: "openai-codex-responses",
 			provider: "openai-codex",
 			baseUrl: CODEX_BASE_URL,
 			reasoning: true,
 			input: ["text", "image"],
-			cost: { input: 0.25, output: 2, cacheRead: 0.025, cacheWrite: 0 },
-			contextWindow: CODEX_CONTEXT,
-			maxTokens: CODEX_MAX_TOKENS,
-		},
-		{
-			id: "gpt-5-codex",
-			name: "gpt-5-codex",
-			api: "openai-codex-responses",
-			provider: "openai-codex",
-			baseUrl: CODEX_BASE_URL,
-			reasoning: true,
-			input: ["text", "image"],
-			cost: { input: 1.25, output: 10, cacheRead: 0.125, cacheWrite: 0 },
-			contextWindow: CODEX_CONTEXT,
-			maxTokens: CODEX_MAX_TOKENS,
-		},
-		{
-			id: "gpt-5.1",
-			name: "GPT-5.1",
-			api: "openai-codex-responses",
-			provider: "openai-codex",
-			baseUrl: CODEX_BASE_URL,
-			reasoning: true,
-			input: ["text", "image"],
-			cost: { input: 1.25, output: 10, cacheRead: 0.125, cacheWrite: 0 },
-			contextWindow: CODEX_CONTEXT,
-			maxTokens: CODEX_MAX_TOKENS,
-		},
-		{
-			id: "gpt-5.1-chat-latest",
-			name: "gpt-5.1-chat-latest",
-			api: "openai-codex-responses",
-			provider: "openai-codex",
-			baseUrl: CODEX_BASE_URL,
-			reasoning: true,
-			input: ["text", "image"],
-			cost: { input: 1.25, output: 10, cacheRead: 0.125, cacheWrite: 0 },
-			contextWindow: CODEX_CONTEXT,
-			maxTokens: CODEX_MAX_TOKENS,
-		},
-		{
-			id: "gpt-5",
-			name: "gpt-5",
-			api: "openai-codex-responses",
-			provider: "openai-codex",
-			baseUrl: CODEX_BASE_URL,
-			reasoning: true,
-			input: ["text", "image"],
-			cost: { input: 1.25, output: 10, cacheRead: 0.125, cacheWrite: 0 },
-			contextWindow: CODEX_CONTEXT,
-			maxTokens: CODEX_MAX_TOKENS,
-		},
-		{
-			id: "gpt-5-mini",
-			name: "gpt-5-mini",
-			api: "openai-codex-responses",
-			provider: "openai-codex",
-			baseUrl: CODEX_BASE_URL,
-			reasoning: true,
-			input: ["text", "image"],
-			cost: { input: 0.25, output: 2, cacheRead: 0.025, cacheWrite: 0 },
-			contextWindow: CODEX_CONTEXT,
-			maxTokens: CODEX_MAX_TOKENS,
-		},
-		{
-			id: "gpt-5-nano",
-			name: "gpt-5-nano",
-			api: "openai-codex-responses",
-			provider: "openai-codex",
-			baseUrl: CODEX_BASE_URL,
-			reasoning: true,
-			input: ["text", "image"],
-			cost: { input: 0.05, output: 0.4, cacheRead: 0.005, cacheWrite: 0 },
+			cost: { input: 1.75, output: 14, cacheRead: 0.175, cacheWrite: 0 },
 			contextWindow: CODEX_CONTEXT,
 			maxTokens: CODEX_MAX_TOKENS,
 		},
diff --git a/packages/ai/src/models.generated.ts b/packages/ai/src/models.generated.ts
index 82bebbc7..4e86ee0d 100644
--- a/packages/ai/src/models.generated.ts
+++ b/packages/ai/src/models.generated.ts
@@ -415,6 +415,23 @@ export const MODELS = {
 			contextWindow: 131072,
 			maxTokens: 40960,
 		} satisfies Model<"openai-completions">,
+		"zai-glm-4.7": {
+			id: "zai-glm-4.7",
+			name: "Z.AI GLM-4.7",
+			api: "openai-completions",
+			provider: "cerebras",
+			baseUrl: "https://api.cerebras.ai/v1",
+			reasoning: false,
+			input: ["text"],
+			cost: {
+				input: 0,
+				output: 0,
+				cacheRead: 0,
+				cacheWrite: 0,
+			},
+			contextWindow: 131072,
+			maxTokens: 40000,
+		} satisfies Model<"openai-completions">,
 	},
 	"github-copilot": {
 		"claude-haiku-4.5": {
@@ -2774,108 +2791,6 @@ export const MODELS = {
 		} satisfies Model<"openai-responses">,
 	},
 	"openai-codex": {
-		"codex-mini-latest": {
-			id: "codex-mini-latest",
-			name: "Codex Mini Latest",
-			api: "openai-codex-responses",
-			provider: "openai-codex",
-			baseUrl: "https://chatgpt.com/backend-api",
-			reasoning: true,
-			input: ["text", "image"],
-			cost: {
-				input: 1.5,
-				output: 6,
-				cacheRead: 0.375,
-				cacheWrite: 0,
-			},
-			contextWindow: 400000,
-			maxTokens: 128000,
-		} satisfies Model<"openai-codex-responses">,
-		"gpt-5": {
-			id: "gpt-5",
-			name: "gpt-5",
-			api: "openai-codex-responses",
-			provider: "openai-codex",
-			baseUrl: "https://chatgpt.com/backend-api",
-			reasoning: true,
-			input: ["text", "image"],
-			cost: {
-				input: 1.25,
-				output: 10,
-				cacheRead: 0.125,
-				cacheWrite: 0,
-			},
-			contextWindow: 400000,
-			maxTokens: 128000,
-		} satisfies Model<"openai-codex-responses">,
-		"gpt-5-codex": {
-			id: "gpt-5-codex",
-			name: "gpt-5-codex",
-			api: "openai-codex-responses",
-			provider: "openai-codex",
-			baseUrl: "https://chatgpt.com/backend-api",
-			reasoning: true,
-			input: ["text", "image"],
-			cost: {
-				input: 1.25,
-				output: 10,
-				cacheRead: 0.125,
-				cacheWrite: 0,
-			},
-			contextWindow: 400000,
-			maxTokens: 128000,
-		} satisfies Model<"openai-codex-responses">,
-		"gpt-5-codex-mini": {
-			id: "gpt-5-codex-mini",
-			name: "gpt-5-codex-mini",
-			api: "openai-codex-responses",
-			provider: "openai-codex",
-			baseUrl: "https://chatgpt.com/backend-api",
-			reasoning: true,
-			input: ["text", "image"],
-			cost: {
-				input: 0.25,
-				output: 2,
-				cacheRead: 0.025,
-				cacheWrite: 0,
-			},
-			contextWindow: 400000,
-			maxTokens: 128000,
-		} satisfies Model<"openai-codex-responses">,
-		"gpt-5-mini": {
-			id: "gpt-5-mini",
-			name: "gpt-5-mini",
-			api: "openai-codex-responses",
-			provider: "openai-codex",
-			baseUrl: "https://chatgpt.com/backend-api",
-			reasoning: true,
-			input: ["text", "image"],
-			cost: {
-				input: 0.25,
-				output: 2,
-				cacheRead: 0.025,
-				cacheWrite: 0,
-			},
-			contextWindow: 400000,
-			maxTokens: 128000,
-		} satisfies Model<"openai-codex-responses">,
-		"gpt-5-nano": {
-			id: "gpt-5-nano",
-			name: "gpt-5-nano",
-			api: "openai-codex-responses",
-			provider: "openai-codex",
-			baseUrl: "https://chatgpt.com/backend-api",
-			reasoning: true,
-			input: ["text", "image"],
-			cost: {
-				input: 0.05,
-				output: 0.4,
-				cacheRead: 0.005,
-				cacheWrite: 0,
-			},
-			contextWindow: 400000,
-			maxTokens: 128000,
-		} satisfies Model<"openai-codex-responses">,
 		"gpt-5.1": {
 			id: "gpt-5.1",
 			name: "GPT-5.1",
@@ -2890,42 +2805,8 @@ export const MODELS = {
 				cacheRead: 0.125,
 				cacheWrite: 0,
 			},
-			contextWindow: 400000,
-			maxTokens: 128000,
-		} satisfies Model<"openai-codex-responses">,
-		"gpt-5.1-chat-latest": {
-			id: "gpt-5.1-chat-latest",
-			name: "gpt-5.1-chat-latest",
-			api: "openai-codex-responses",
-			provider: "openai-codex",
-			baseUrl: "https://chatgpt.com/backend-api",
-			reasoning: true,
-			input: ["text", "image"],
-			cost: {
-				input: 1.25,
-				output: 10,
-				cacheRead: 0.125,
-				cacheWrite: 0,
-			},
-			contextWindow: 400000,
-			maxTokens: 128000,
-		} satisfies Model<"openai-codex-responses">,
-		"gpt-5.1-codex": {
-			id: "gpt-5.1-codex",
-			name: "GPT-5.1 Codex",
-			api: "openai-codex-responses",
-			provider: "openai-codex",
-			baseUrl: "https://chatgpt.com/backend-api",
-			reasoning: true,
-			input: ["text", "image"],
-			cost: {
-				input: 1.25,
-				output: 10,
-				cacheRead: 0.125,
-				cacheWrite: 0,
-			},
-			contextWindow: 400000,
-			maxTokens: 128000,
+			contextWindow: 272000,
+			maxTokens: 10000,
 		} satisfies Model<"openai-codex-responses">,
 		"gpt-5.1-codex-max": {
 			id: "gpt-5.1-codex-max",
@@ -2941,8 +2822,8 @@ export const MODELS = {
 				cacheRead: 0.125,
 				cacheWrite: 0,
 			},
-			contextWindow: 400000,
-			maxTokens: 128000,
+			contextWindow: 272000,
+			maxTokens: 10000,
 		} satisfies Model<"openai-codex-responses">,
 		"gpt-5.1-codex-mini": {
 			id: "gpt-5.1-codex-mini",
@@ -2958,8 +2839,8 @@ export const MODELS = {
 				cacheRead: 0.025,
 				cacheWrite: 0,
 			},
-			contextWindow: 400000,
-			maxTokens: 128000,
+			contextWindow: 272000,
+			maxTokens: 10000,
 		} satisfies Model<"openai-codex-responses">,
 		"gpt-5.2": {
 			id: "gpt-5.2",
@@ -2975,8 +2856,8 @@ export const MODELS = {
 				cacheRead: 0.175,
 				cacheWrite: 0,
 			},
-			contextWindow: 400000,
-			maxTokens: 128000,
+			contextWindow: 272000,
+			maxTokens: 10000,
 		} satisfies Model<"openai-codex-responses">,
 		"gpt-5.2-codex": {
 			id: "gpt-5.2-codex",
@@ -2992,8 +2873,8 @@ export const MODELS = {
 				cacheRead: 0.175,
 				cacheWrite: 0,
 			},
-			contextWindow: 400000,
-			maxTokens: 128000,
+			contextWindow: 272000,
+			maxTokens: 10000,
 		} satisfies Model<"openai-codex-responses">,
 	},
 	"openrouter": {
diff --git a/packages/ai/src/providers/openai-codex-responses.ts b/packages/ai/src/providers/openai-codex-responses.ts
index 0f74b635..74cb2206 100644
--- a/packages/ai/src/providers/openai-codex-responses.ts
+++ b/packages/ai/src/providers/openai-codex-responses.ts
@@ -37,7 +37,6 @@ import { buildCodexPiBridge } from "./openai-codex/prompts/pi-codex-bridge.js";
 import { buildCodexSystemPrompt } from "./openai-codex/prompts/system-prompt.js";
 import {
 	type CodexRequestOptions,
-	normalizeModel,
 	type RequestBody,
 	transformRequestBody,
 } from "./openai-codex/request-transformer.js";
@@ -111,8 +110,7 @@ export const streamOpenAICodexResponses: StreamFunction<"openai-codex-responses"
 				params.tools = convertTools(context.tools);
 			}
 
-			const normalizedModel = normalizeModel(params.model);
-			const codexInstructions = await getCodexInstructions(normalizedModel);
+			const codexInstructions = await getCodexInstructions(params.model);
 			const bridgeText = buildCodexPiBridge(context.tools);
 			const systemPrompt = buildCodexSystemPrompt({
 				codexInstructions,
@@ -120,7 +118,6 @@ export const streamOpenAICodexResponses: StreamFunction<"openai-codex-responses"
 				userSystemPrompt: context.systemPrompt,
 			});
 
-			params.model = normalizedModel;
 			params.instructions = systemPrompt.instructions;
 
 			const codexOptions: CodexRequestOptions = {
diff --git a/packages/ai/src/providers/openai-codex/prompts/codex.ts b/packages/ai/src/providers/openai-codex/prompts/codex.ts
index db94e780..869add2e 100644
--- a/packages/ai/src/providers/openai-codex/prompts/codex.ts
+++ b/packages/ai/src/providers/openai-codex/prompts/codex.ts
@@ -44,17 +44,17 @@ export type CacheMetadata = {
 	url: string;
 };
 
-export function getModelFamily(normalizedModel: string): ModelFamily {
-	if (normalizedModel.includes("gpt-5.2-codex") || normalizedModel.includes("gpt 5.2 codex")) {
+export function getModelFamily(model: string): ModelFamily {
+	if (model.includes("gpt-5.2-codex") || model.includes("gpt 5.2 codex")) {
 		return "gpt-5.2-codex";
 	}
-	if (normalizedModel.includes("codex-max")) {
+	if (model.includes("codex-max")) {
 		return "codex-max";
 	}
-	if (normalizedModel.includes("codex") || normalizedModel.startsWith("codex-")) {
+	if (model.includes("codex") || model.startsWith("codex-")) {
 		return "codex";
 	}
-	if (normalizedModel.includes("gpt-5.2")) {
+	if (model.includes("gpt-5.2")) {
 		return "gpt-5.2";
 	}
 	return "gpt-5.1";
@@ -96,8 +96,8 @@ async function getLatestReleaseTag(): Promise<string> {
 	throw new Error("Failed to determine latest release tag from GitHub");
 }
 
-export async function getCodexInstructions(normalizedModel = "gpt-5.1-codex"): Promise<string> {
-	const modelFamily = getModelFamily(normalizedModel);
+export async function getCodexInstructions(model = "gpt-5.1-codex"): Promise<string> {
+	const modelFamily = getModelFamily(model);
 	const promptFile = PROMPT_FILES[modelFamily];
 	const cacheDir = getCacheDir();
 	const cacheFile = join(cacheDir, CACHE_FILES[modelFamily]);
diff --git a/packages/ai/src/providers/openai-codex/request-transformer.ts b/packages/ai/src/providers/openai-codex/request-transformer.ts
index 32b21e59..bd3f9926 100644
--- a/packages/ai/src/providers/openai-codex/request-transformer.ts
+++ b/packages/ai/src/providers/openai-codex/request-transformer.ts
@@ -41,155 +41,26 @@ export interface RequestBody {
 	[key: string]: unknown;
 }
 
-const MODEL_MAP: Record<string, string> = {
-	"gpt-5.1-codex": "gpt-5.1-codex",
-	"gpt-5.1-codex-low": "gpt-5.1-codex",
-	"gpt-5.1-codex-medium": "gpt-5.1-codex",
-	"gpt-5.1-codex-high": "gpt-5.1-codex",
-	"gpt-5.1-codex-max": "gpt-5.1-codex-max",
-	"gpt-5.1-codex-max-low": "gpt-5.1-codex-max",
-	"gpt-5.1-codex-max-medium": "gpt-5.1-codex-max",
-	"gpt-5.1-codex-max-high": "gpt-5.1-codex-max",
-	"gpt-5.1-codex-max-xhigh": "gpt-5.1-codex-max",
-	"gpt-5.2": "gpt-5.2",
-	"gpt-5.2-none": "gpt-5.2",
-	"gpt-5.2-low": "gpt-5.2",
-	"gpt-5.2-medium": "gpt-5.2",
-	"gpt-5.2-high": "gpt-5.2",
-	"gpt-5.2-xhigh": "gpt-5.2",
-	"gpt-5.2-codex": "gpt-5.2-codex",
-	"gpt-5.2-codex-low": "gpt-5.2-codex",
-	"gpt-5.2-codex-medium": "gpt-5.2-codex",
-	"gpt-5.2-codex-high": "gpt-5.2-codex",
-	"gpt-5.2-codex-xhigh": "gpt-5.2-codex",
-	"gpt-5.1-codex-mini": "gpt-5.1-codex-mini",
-	"gpt-5.1-codex-mini-medium": "gpt-5.1-codex-mini",
-	"gpt-5.1-codex-mini-high": "gpt-5.1-codex-mini",
-	"gpt-5.1": "gpt-5.1",
-	"gpt-5.1-none": "gpt-5.1",
-	"gpt-5.1-low": "gpt-5.1",
-	"gpt-5.1-medium": "gpt-5.1",
-	"gpt-5.1-high": "gpt-5.1",
-	"gpt-5.1-chat-latest": "gpt-5.1",
-	"gpt-5-codex": "gpt-5.1-codex",
-	"codex-mini-latest": "gpt-5.1-codex-mini",
-	"gpt-5-codex-mini": "gpt-5.1-codex-mini",
-	"gpt-5-codex-mini-medium": "gpt-5.1-codex-mini",
-	"gpt-5-codex-mini-high": "gpt-5.1-codex-mini",
-	"gpt-5": "gpt-5.1",
-	"gpt-5-mini": "gpt-5.1",
-	"gpt-5-nano": "gpt-5.1",
-};
-
-function getNormalizedModel(modelId: string): string | undefined {
-	if (MODEL_MAP[modelId]) return MODEL_MAP[modelId];
-	const lowerModelId = modelId.toLowerCase();
-	const match = Object.keys(MODEL_MAP).find((key) => key.toLowerCase() === lowerModelId);
-	return match ? MODEL_MAP[match] : undefined;
-}
-
-export function normalizeModel(model: string | undefined): string {
-	if (!model) return "gpt-5.1";
-
+function clampReasoningEffort(model: string, effort: ReasoningConfig["effort"]): ReasoningConfig["effort"] {
+	// Codex backend expects exact model IDs. Do not normalize model names here.
 	const modelId = model.includes("/") ? model.split("/").pop()! : model;
-	const mappedModel = getNormalizedModel(modelId);
-	if (mappedModel) return mappedModel;
 
-	const normalized = modelId.toLowerCase();
-
-	if (normalized.includes("gpt-5.2-codex") || normalized.includes("gpt 5.2 codex")) {
-		return "gpt-5.2-codex";
-	}
-	if (normalized.includes("gpt-5.2") || normalized.includes("gpt 5.2")) {
-		return "gpt-5.2";
-	}
-	if (normalized.includes("gpt-5.1-codex-max") || normalized.includes("gpt 5.1 codex max")) {
-		return "gpt-5.1-codex-max";
-	}
-	if (normalized.includes("gpt-5.1-codex-mini") || normalized.includes("gpt 5.1 codex mini")) {
-		return "gpt-5.1-codex-mini";
-	}
-	if (
-		normalized.includes("codex-mini-latest") ||
-		normalized.includes("gpt-5-codex-mini") ||
-		normalized.includes("gpt 5 codex mini")
-	) {
-		return "codex-mini-latest";
-	}
-	if (normalized.includes("gpt-5.1-codex") || normalized.includes("gpt 5.1 codex")) {
-		return "gpt-5.1-codex";
-	}
-	if (normalized.includes("gpt-5.1") || normalized.includes("gpt 5.1")) {
-		return "gpt-5.1";
-	}
-	if (normalized.includes("codex")) {
-		return "gpt-5.1-codex";
-	}
-	if (normalized.includes("gpt-5") || normalized.includes("gpt 5")) {
-		return "gpt-5.1";
+	// gpt-5.1 does not support xhigh.
+	if (modelId === "gpt-5.1" && effort === "xhigh") {
+		return "high";
 	}
 
-	return "gpt-5.1";
+	// gpt-5.1-codex-mini only supports medium/high.
+	if (modelId === "gpt-5.1-codex-mini") {
+		return effort === "high" || effort === "xhigh" ? "high" : "medium";
+	}
+
+	return effort;
 }
 
-function getReasoningConfig(modelName: string | undefined, options: CodexRequestOptions = {}): ReasoningConfig {
-	const normalizedName = modelName?.toLowerCase() ?? "";
-
-	const isGpt52Codex = normalizedName.includes("gpt-5.2-codex") || normalizedName.includes("gpt 5.2 codex");
-	const isGpt52General = (normalizedName.includes("gpt-5.2") || normalizedName.includes("gpt 5.2")) && !isGpt52Codex;
-	const isCodexMax = normalizedName.includes("codex-max") || normalizedName.includes("codex max");
-	const isCodexMini =
-		normalizedName.includes("codex-mini") ||
-		normalizedName.includes("codex mini") ||
-		normalizedName.includes("codex_mini") ||
-		normalizedName.includes("codex-mini-latest");
-	const isCodex = normalizedName.includes("codex") && !isCodexMini;
-	const isLightweight = !isCodexMini && (normalizedName.includes("nano") || normalizedName.includes("mini"));
-	const isGpt51General =
-		(normalizedName.includes("gpt-5.1") || normalizedName.includes("gpt 5.1")) &&
-		!isCodex &&
-		!isCodexMax &&
-		!isCodexMini;
-
-	const supportsXhigh = isGpt52General || isGpt52Codex || isCodexMax;
-	const supportsNone = isGpt52General || isGpt51General;
-
-	const defaultEffort: ReasoningConfig["effort"] = isCodexMini
-		? "medium"
-		: supportsXhigh
-			? "high"
-			: isLightweight
-				? "minimal"
-				: "medium";
-
-	let effort = options.reasoningEffort || defaultEffort;
-
-	if (isCodexMini) {
-		if (effort === "minimal" || effort === "low" || effort === "none") {
-			effort = "medium";
-		}
-		if (effort === "xhigh") {
-			effort = "high";
-		}
-		if (effort !== "high" && effort !== "medium") {
-			effort = "medium";
-		}
-	}
-
-	if (!supportsXhigh && effort === "xhigh") {
-		effort = "high";
-	}
-
-	if (!supportsNone && effort === "none") {
-		effort = "low";
-	}
-
-	if (isCodex && effort === "minimal") {
-		effort = "low";
-	}
-
+function getReasoningConfig(model: string, options: CodexRequestOptions): ReasoningConfig {
 	return {
-		effort,
+		effort: clampReasoningEffort(model, options.reasoningEffort as ReasoningConfig["effort"]),
 		summary: options.reasoningSummary ?? "auto",
 	};
 }
@@ -213,9 +84,6 @@ export async function transformRequestBody(
 	options: CodexRequestOptions = {},
 	prompt?: { instructions: string; developerMessages: string[] },
 ): Promise<RequestBody> {
-	const normalizedModel = normalizeModel(body.model);
-
-	body.model = normalizedModel;
 	body.store = false;
 	body.stream = true;
 
@@ -270,7 +138,7 @@ export async function transformRequestBody(
 	}
 
 	if (options.reasoningEffort !== undefined) {
-		const reasoningConfig = getReasoningConfig(normalizedModel, options);
+		const reasoningConfig = getReasoningConfig(body.model, options);
 		body.reasoning = {
 			...body.reasoning,
 			...reasoningConfig,
diff --git a/packages/ai/test/openai-codex.test.ts b/packages/ai/test/openai-codex.test.ts
index c2b91dd8..9252656b 100644
--- a/packages/ai/test/openai-codex.test.ts
+++ b/packages/ai/test/openai-codex.test.ts
@@ -3,11 +3,7 @@ import { tmpdir } from "node:os";
 import { join } from "node:path";
 import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
 import { getCodexInstructions } from "../src/providers/openai-codex/prompts/codex.js";
-import {
-	normalizeModel,
-	type RequestBody,
-	transformRequestBody,
-} from "../src/providers/openai-codex/request-transformer.js";
+import { type RequestBody, transformRequestBody } from "../src/providers/openai-codex/request-transformer.js";
 import { parseCodexError } from "../src/providers/openai-codex/response-handler.js";
 
 const DEFAULT_PROMPT_PREFIX =
@@ -59,9 +55,21 @@ describe("openai-codex request transformer", () => {
 	});
 });
 
-describe("openai-codex model normalization", () => {
-	it("maps space-separated codex-mini names to codex-mini-latest", () => {
-		expect(normalizeModel("gpt 5 codex mini")).toBe("codex-mini-latest");
+describe("openai-codex reasoning effort clamping", () => {
+	it("clamps gpt-5.1 xhigh to high", async () => {
+		const body: RequestBody = { model: "gpt-5.1", input: [] };
+		const transformed = await transformRequestBody(body, { reasoningEffort: "xhigh" });
+		expect(transformed.reasoning?.effort).toBe("high");
+	});
+
+	it("clamps gpt-5.1-codex-mini to medium/high only", async () => {
+		const body: RequestBody = { model: "gpt-5.1-codex-mini", input: [] };
+
+		const low = await transformRequestBody({ ...body }, { reasoningEffort: "low" });
+		expect(low.reasoning?.effort).toBe("medium");
+
+		const xhigh = await transformRequestBody({ ...body }, { reasoningEffort: "xhigh" });
+		expect(xhigh.reasoning?.effort).toBe("high");
 	});
 });