feat: add GPT-5.4 Codex fast mode models (codex, spark variants)

Adds three new model entries to the OpenAI Codex provider:
- gpt-5.4-codex: Full GPT-5.4 optimized for agentic coding (1M context)
- gpt-5.4-codex-spark: Fast, text-only GPT-5.4 variant (128k context, 8k output)
- gpt-5.4-mini-codex-spark: Fast, text-only GPT-5.4 Mini variant (128k context, 8k output)

Follows the same pattern as existing gpt-5.3-codex and gpt-5.3-codex-spark models.

Closes #12112

Author: roomote

packages/types/src/providers/openai-codex.ts

@@ -172,6 +172,48 @@ export const openAiCodexModels = {
 		supportsTemperature: false,
 		description: "GPT-5.1 Codex Mini: Faster version for coding tasks via ChatGPT subscription",
 	},
+	"gpt-5.4-codex": {
+		maxTokens: 128000,
+		contextWindow: 1_050_000,
+		includedTools: ["apply_patch"],
+		excludedTools: ["apply_diff", "write_to_file"],
+		supportsImages: true,
+		supportsPromptCache: true,
+		supportsReasoningEffort: ["low", "medium", "high", "xhigh"],
+		reasoningEffort: "medium",
+		inputPrice: 0,
+		outputPrice: 0,
+		supportsTemperature: false,
+		description: "GPT-5.4 Codex: GPT-5.4 optimized for agentic coding via ChatGPT subscription",
+	},
+	"gpt-5.4-codex-spark": {
+		maxTokens: 8192,
+		contextWindow: 128000,
+		includedTools: ["apply_patch"],
+		excludedTools: ["apply_diff", "write_to_file"],
+		supportsImages: false,
+		supportsPromptCache: true,
+		supportsReasoningEffort: ["low", "medium", "high", "xhigh"],
+		reasoningEffort: "medium",
+		inputPrice: 0,
+		outputPrice: 0,
+		supportsTemperature: false,
+		description: "GPT-5.4 Codex Spark: Fast, text-only coding model via ChatGPT subscription",
+	},
+	"gpt-5.4-mini-codex-spark": {
+		maxTokens: 8192,
+		contextWindow: 128000,
+		includedTools: ["apply_patch"],
+		excludedTools: ["apply_diff", "write_to_file"],
+		supportsImages: false,
+		supportsPromptCache: true,
+		supportsReasoningEffort: ["low", "medium", "high", "xhigh"],
+		reasoningEffort: "medium",
+		inputPrice: 0,
+		outputPrice: 0,
+		supportsTemperature: false,
+		description: "GPT-5.4 Mini Codex Spark: Fast, text-only mini coding model via ChatGPT subscription",
+	},
 	"gpt-5.4": {
 		maxTokens: 128000,
 		contextWindow: 1_050_000,

src/api/providers/__tests__/openai-codex.spec.ts

@@ -3,18 +3,25 @@
 import { OpenAiCodexHandler } from "../openai-codex"
 
 describe("OpenAiCodexHandler.getModel", () => {
-	it.each(["gpt-5.1", "gpt-5", "gpt-5.1-codex", "gpt-5-codex", "gpt-5-codex-mini", "gpt-5.3-codex-spark"])(
-		"should return specified model when a valid model id is provided: %s",
-		(apiModelId) => {
-			const handler = new OpenAiCodexHandler({ apiModelId })
-			const model = handler.getModel()
-
-			expect(model.id).toBe(apiModelId)
-			expect(model.info).toBeDefined()
-			// Default reasoning effort for GPT-5 family
-			expect(model.info.reasoningEffort).toBe("medium")
-		},
-	)
+	it.each([
+		"gpt-5.1",
+		"gpt-5",
+		"gpt-5.1-codex",
+		"gpt-5-codex",
+		"gpt-5-codex-mini",
+		"gpt-5.3-codex-spark",
+		"gpt-5.4-codex",
+		"gpt-5.4-codex-spark",
+		"gpt-5.4-mini-codex-spark",
+	])("should return specified model when a valid model id is provided: %s", (apiModelId) => {
+		const handler = new OpenAiCodexHandler({ apiModelId })
+		const model = handler.getModel()
+
+		expect(model.id).toBe(apiModelId)
+		expect(model.info).toBeDefined()
+		// Default reasoning effort for GPT-5 family
+		expect(model.info.reasoningEffort).toBe("medium")
+	})
 
 	it("should fall back to default model when an invalid model id is provided", () => {
 		const handler = new OpenAiCodexHandler({ apiModelId: "not-a-real-model" })
@@ -41,4 +48,35 @@ describe("OpenAiCodexHandler.getModel", () => {
 		expect(model.id).toBe("gpt-5.4-mini")
 		expect(model.info).toBeDefined()
 	})
+
+	it("should use GPT-5.4 Codex capabilities when selected", () => {
+		const handler = new OpenAiCodexHandler({ apiModelId: "gpt-5.4-codex" })
+		const model = handler.getModel()
+
+		expect(model.id).toBe("gpt-5.4-codex")
+		expect(model.info.contextWindow).toBe(1_050_000)
+		expect(model.info.maxTokens).toBe(128000)
+		expect(model.info.supportsImages).toBe(true)
+		expect(model.info.reasoningEffort).toBe("medium")
+	})
+
+	it("should use GPT-5.4 Codex Spark-specific limits and capabilities", () => {
+		const handler = new OpenAiCodexHandler({ apiModelId: "gpt-5.4-codex-spark" })
+		const model = handler.getModel()
+
+		expect(model.id).toBe("gpt-5.4-codex-spark")
+		expect(model.info.contextWindow).toBe(128000)
+		expect(model.info.maxTokens).toBe(8192)
+		expect(model.info.supportsImages).toBe(false)
+	})
+
+	it("should use GPT-5.4 Mini Codex Spark-specific limits and capabilities", () => {
+		const handler = new OpenAiCodexHandler({ apiModelId: "gpt-5.4-mini-codex-spark" })
+		const model = handler.getModel()
+
+		expect(model.id).toBe("gpt-5.4-mini-codex-spark")
+		expect(model.info.contextWindow).toBe(128000)
+		expect(model.info.maxTokens).toBe(8192)
+		expect(model.info.supportsImages).toBe(false)
+	})
 })