diff --git a/packages/ai/scripts/generate-models.ts b/packages/ai/scripts/generate-models.ts
index 66b36f8c..068250ce 100644
--- a/packages/ai/scripts/generate-models.ts
+++ b/packages/ai/scripts/generate-models.ts
@@ -677,8 +677,17 @@ async function generateModels() {
 		) {
 			candidate.contextWindow = 200000;
 		}
+		if ((candidate.provider === "opencode" || candidate.provider === "opencode-go") && candidate.id === "gpt-5.4") {
+			candidate.contextWindow = 272000;
+			candidate.maxTokens = 128000;
+		}
+		if (candidate.provider === "openai" && candidate.id === "gpt-5.4") {
+			candidate.contextWindow = 272000;
+			candidate.maxTokens = 128000;
+		}
 	}
 
+
 	// Add missing EU Opus 4.6 profile
 	if (!allModels.some((m) => m.provider === "amazon-bedrock" && m.id === "eu.anthropic.claude-opus-4-6-v1")) {
 		allModels.push({
@@ -858,6 +867,26 @@ async function generateModels() {
 		}
 	}
 
+	if (!allModels.some((m) => m.provider === "openai" && m.id === "gpt-5.4")) {
+		allModels.push({
+			id: "gpt-5.4",
+			name: "GPT-5.4",
+			api: "openai-responses",
+			baseUrl: "https://api.openai.com/v1",
+			provider: "openai",
+			reasoning: true,
+			input: ["text", "image"],
+			cost: {
+				input: 2.5,
+				output: 15,
+				cacheRead: 0.25,
+				cacheWrite: 0,
+			},
+			contextWindow: 272000,
+			maxTokens: 128000,
+		});
+	}
+
 	// 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.
@@ -937,6 +966,18 @@ async function generateModels() {
 			contextWindow: CODEX_CONTEXT,
 			maxTokens: CODEX_MAX_TOKENS,
 		},
+		{
+			id: "gpt-5.4",
+			name: "GPT-5.4",
+			api: "openai-codex-responses",
+			provider: "openai-codex",
+			baseUrl: CODEX_BASE_URL,
+			reasoning: true,
+			input: ["text", "image"],
+			cost: { input: 2.5, output: 15, cacheRead: 0.25, cacheWrite: 0 },
+			contextWindow: CODEX_CONTEXT,
+			maxTokens: CODEX_MAX_TOKENS,
+		},
 		{
 			id: "gpt-5.3-codex-spark",
 			name: "GPT-5.3 Codex Spark",
diff --git a/packages/ai/src/models.ts b/packages/ai/src/models.ts
index 459b1be2..3c06c0cc 100644
--- a/packages/ai/src/models.ts
+++ b/packages/ai/src/models.ts
@@ -49,11 +49,11 @@ export function calculateCost<TApi extends Api>(model: Model<TApi>, usage: Usage
  * Check if a model supports xhigh thinking level.
  *
  * Supported today:
- * - GPT-5.2 / GPT-5.3 model families
+ * - GPT-5.2 / GPT-5.3 / GPT-5.4 model families
  * - Anthropic Messages API Opus 4.6 models (xhigh maps to adaptive effort "max")
  */
 export function supportsXhigh<TApi extends Api>(model: Model<TApi>): boolean {
-	if (model.id.includes("gpt-5.2") || model.id.includes("gpt-5.3")) {
+	if (model.id.includes("gpt-5.2") || model.id.includes("gpt-5.3") || model.id.includes("gpt-5.4")) {
 		return true;
 	}
 
diff --git a/packages/ai/src/providers/openai-codex-responses.ts b/packages/ai/src/providers/openai-codex-responses.ts
index 96de4cc7..90ec3ecd 100644
--- a/packages/ai/src/providers/openai-codex-responses.ts
+++ b/packages/ai/src/providers/openai-codex-responses.ts
@@ -324,7 +324,8 @@ function buildRequestBody(
 
 function clampReasoningEffort(modelId: string, effort: string): string {
 	const id = modelId.includes("/") ? modelId.split("/").pop()! : modelId;
-	if ((id.startsWith("gpt-5.2") || id.startsWith("gpt-5.3")) && effort === "minimal") return "low";
+	if ((id.startsWith("gpt-5.2") || id.startsWith("gpt-5.3") || id.startsWith("gpt-5.4")) && effort === "minimal")
+		return "low";
 	if (id === "gpt-5.1" && effort === "xhigh") return "high";
 	if (id === "gpt-5.1-codex-mini") return effort === "high" || effort === "xhigh" ? "high" : "medium";
 	return effort;
diff --git a/packages/coding-agent/src/core/model-resolver.ts b/packages/coding-agent/src/core/model-resolver.ts
index 9549f81b..b0e7743f 100644
--- a/packages/coding-agent/src/core/model-resolver.ts
+++ b/packages/coding-agent/src/core/model-resolver.ts
@@ -14,9 +14,9 @@ import type { ModelRegistry } from "./model-registry.js";
 export const defaultModelPerProvider: Record<KnownProvider, string> = {
 	"amazon-bedrock": "us.anthropic.claude-opus-4-6-v1",
 	anthropic: "claude-opus-4-6",
-	openai: "gpt-5.1-codex",
+	openai: "gpt-5.4",
 	"azure-openai-responses": "gpt-5.2",
-	"openai-codex": "gpt-5.3-codex",
+	"openai-codex": "gpt-5.4",
 	google: "gemini-2.5-pro",
 	"google-gemini-cli": "gemini-2.5-pro",
 	"google-antigravity": "gemini-3.1-pro-high",