Add Codex provider integration

Author: Andrei Ungureanu

packages/types/src/provider-settings.ts

@@ -8,6 +8,7 @@ import {
 	cerebrasModels,
 	chutesModels,
 	claudeCodeModels,
+	codexModels,
 	deepSeekModels,
 	doubaoModels,
 	featherlessModels,
@@ -122,6 +123,7 @@ export const providerNames = [
 	"cerebras",
 	"chutes",
 	"claude-code",
+	"codex",
 	"doubao",
 	"deepseek",
 	"featherless",
@@ -254,6 +256,15 @@ const openAiSchema = baseProviderSettingsSchema.extend({
 	openAiHeaders: z.record(z.string(), z.string()).optional(),
 })
 
+// Codex shares OpenAI settings and adds optional CLI config & binary paths for seamless auth
+const codexSchema = openAiSchema.extend({
+	apiModelId: z.string().optional(),
+	codexCliConfigPath: z.string().optional(),
+	codexCliPath: z.string().optional(),
+	codexDebugEnabled: z.boolean().optional(),
+	codexDebugLogPath: z.string().optional(),
+})
+
 const ollamaSchema = baseProviderSettingsSchema.extend({
 	ollamaModelId: z.string().optional(),
 	ollamaBaseUrl: z.string().optional(),
@@ -418,6 +429,7 @@ const defaultSchema = z.object({
 export const providerSettingsSchemaDiscriminated = z.discriminatedUnion("apiProvider", [
 	anthropicSchema.merge(z.object({ apiProvider: z.literal("anthropic") })),
 	claudeCodeSchema.merge(z.object({ apiProvider: z.literal("claude-code") })),
+	codexSchema.merge(z.object({ apiProvider: z.literal("codex") })),
 	glamaSchema.merge(z.object({ apiProvider: z.literal("glama") })),
 	openRouterSchema.merge(z.object({ apiProvider: z.literal("openrouter") })),
 	bedrockSchema.merge(z.object({ apiProvider: z.literal("bedrock") })),
@@ -459,6 +471,7 @@ export const providerSettingsSchema = z.object({
 	apiProvider: providerNamesSchema.optional(),
 	...anthropicSchema.shape,
 	...claudeCodeSchema.shape,
+	...codexSchema.shape,
 	...glamaSchema.shape,
 	...openRouterSchema.shape,
 	...bedrockSchema.shape,
@@ -548,6 +561,7 @@ export const isTypicalProvider = (key: unknown): key is TypicalProvider =>
 export const modelIdKeysByProvider: Record<TypicalProvider, ModelIdKey> = {
 	anthropic: "apiModelId",
 	"claude-code": "apiModelId",
+	codex: "apiModelId",
 	glama: "glamaModelId",
 	openrouter: "openRouterModelId",
 	bedrock: "apiModelId",
@@ -633,6 +647,7 @@ export const MODELS_BY_PROVIDER: Record<
 		models: Object.keys(chutesModels),
 	},
 	"claude-code": { id: "claude-code", label: "Claude Code", models: Object.keys(claudeCodeModels) },
+	codex: { id: "codex", label: "Codex", models: Object.keys(codexModels) },
 	deepseek: {
 		id: "deepseek",
 		label: "DeepSeek",

packages/types/src/providers/codex.ts

@@ -0,0 +1,148 @@
+import type { ModelInfo, ReasoningEffortWithMinimal } from "../model.js"
+import { openAiNativeModels } from "./openai.js"
+
+export type CodexModelId =
+	| "gpt-5-codex"
+	| "gpt-5-codex-minimal"
+	| "gpt-5-codex-low"
+	| "gpt-5-codex-medium"
+	| "gpt-5-codex-high"
+	| "gpt-5"
+	| "gpt-5-minimal"
+	| "gpt-5-low"
+	| "gpt-5-medium"
+	| "gpt-5-high"
+	| "codex-mini-latest"
+
+export type CodexCliModelInfo = {
+	id: string
+	label?: string
+	description?: string
+	model?: string
+	effort?: ReasoningEffortWithMinimal
+}
+
+export interface CodexCliPreset {
+	id: CodexModelId
+	label: string
+	description: string
+	cliModel: string
+	effort?: ReasoningEffortWithMinimal
+}
+
+export const codexDefaultModelId: CodexModelId = "gpt-5-codex"
+
+const CLI_DEFAULT_MODEL = "gpt-5"
+
+const codexBaseModelInfo: ModelInfo = {
+	...openAiNativeModels["gpt-5-2025-08-07"],
+	supportsReasoningEffort: true,
+}
+
+export const codexCliPresets: CodexCliPreset[] = [
+	{
+		id: "gpt-5-codex",
+		label: "gpt-5-codex (auto)",
+		description: "— uses your Codex CLI default reasoning effort",
+		cliModel: CLI_DEFAULT_MODEL,
+	},
+	{
+		id: "gpt-5-codex-minimal",
+		label: "gpt-5-codex minimal",
+		description: "— fastest responses with limited reasoning; ideal for lightweight edits and quick fixes",
+		cliModel: CLI_DEFAULT_MODEL,
+		effort: "minimal",
+	},
+	{
+		id: "gpt-5-codex-low",
+		label: "gpt-5-codex low",
+		description: "— prioritises speed while keeping some reasoning depth for straightforward coding tasks",
+		cliModel: CLI_DEFAULT_MODEL,
+		effort: "low",
+	},
+	{
+		id: "gpt-5-codex-medium",
+		label: "gpt-5-codex medium",
+		description: "— balanced reasoning for everyday development work (Codex CLI default)",
+		cliModel: CLI_DEFAULT_MODEL,
+		effort: "medium",
+	},
+	{
+		id: "gpt-5-codex-high",
+		label: "gpt-5-codex high",
+		description: "— maximum reasoning depth for complex or ambiguous engineering problems",
+		cliModel: CLI_DEFAULT_MODEL,
+		effort: "high",
+	},
+]
+
+const legacyRedirectEntries: ReadonlyArray<[string, CodexModelId]> = [
+	["gpt-5", "gpt-5-codex"],
+	["gpt-5-minimal", "gpt-5-codex-minimal"],
+	["gpt-5-low", "gpt-5-codex-low"],
+	["gpt-5-medium", "gpt-5-codex-medium"],
+	["gpt-5-high", "gpt-5-codex-high"],
+	["gpt-5-codex", "gpt-5-codex"],
+	["gpt-5-codex-minimal", "gpt-5-codex-minimal"],
+	["gpt-5-codex-low", "gpt-5-codex-low"],
+	["gpt-5-codex-medium", "gpt-5-codex-medium"],
+	["gpt-5-codex-high", "gpt-5-codex-high"],
+	["codex-mini-latest", "codex-mini-latest"],
+]
+
+export const codexLegacyModelRedirects: Record<string, CodexModelId> = Object.fromEntries(legacyRedirectEntries)
+
+const presetMap = new Map<CodexModelId, CodexCliPreset>()
+
+for (const preset of codexCliPresets) {
+	presetMap.set(preset.id, preset)
+}
+
+for (const [legacyId, targetId] of legacyRedirectEntries) {
+	const target = presetMap.get(targetId as CodexModelId)
+	if (target && !presetMap.has(legacyId as CodexModelId)) {
+		presetMap.set(legacyId as CodexModelId, {
+			...target,
+			id: legacyId as CodexModelId,
+		})
+	}
+}
+
+const derivedModels: Record<string, ModelInfo> = {}
+
+for (const preset of presetMap.values()) {
+	derivedModels[preset.id] = {
+		...codexBaseModelInfo,
+		description: preset.description || codexBaseModelInfo.description,
+	}
+}
+
+if (openAiNativeModels["codex-mini-latest"]) {
+	derivedModels["codex-mini-latest"] = {
+		...openAiNativeModels["codex-mini-latest"],
+		supportsReasoningEffort: true,
+	}
+}
+
+export const codexModels = derivedModels as Record<CodexModelId, ModelInfo>
+
+export const fallbackCodexCliModels: CodexCliModelInfo[] = codexCliPresets.map((preset) => ({
+	id: preset.id,
+	label: preset.label,
+	description: preset.description,
+	model: preset.cliModel,
+	effort: preset.effort,
+}))
+
+export const normalizeCodexModelId = (id?: string | null): CodexModelId => {
+	const trimmed = (id ?? "").trim()
+	if (!trimmed) {
+		return codexDefaultModelId
+	}
+	return (codexLegacyModelRedirects[trimmed] ?? trimmed) as CodexModelId
+}
+
+export const getCodexPreset = (id: string | undefined) => {
+	const normalized = normalizeCodexModelId(id)
+	return presetMap.get(normalized)
+}

packages/types/src/providers/index.ts

@@ -19,6 +19,7 @@ export * from "./moonshot.js"
 export * from "./ollama.js"
 export * from "./openai.js"
 export * from "./openrouter.js"
+export * from "./codex.js"
 export * from "./qwen-code.js"
 export * from "./requesty.js"
 export * from "./roo.js"

packages/types/src/providers/openai.ts

@@ -37,6 +37,24 @@ export const openAiNativeModels = {
 			{ name: "priority", contextWindow: 400000, inputPrice: 2.5, outputPrice: 20.0, cacheReadsPrice: 0.25 },
 		],
 	},
+	"gpt-5-codex": {
+		maxTokens: 128000,
+		contextWindow: 400000,
+		supportsImages: true,
+		supportsPromptCache: true,
+		supportsReasoningEffort: true,
+		reasoningEffort: "medium",
+		inputPrice: 1.25,
+		outputPrice: 10.0,
+		cacheReadsPrice: 0.13,
+		description: "GPT-5 Codex: Optimized for software engineering workflows with Codex tooling integration",
+		supportsVerbosity: true,
+		supportsTemperature: false,
+		tiers: [
+			{ name: "flex", contextWindow: 400000, inputPrice: 0.625, outputPrice: 5.0, cacheReadsPrice: 0.0625 },
+			{ name: "priority", contextWindow: 400000, inputPrice: 2.5, outputPrice: 20.0, cacheReadsPrice: 0.25 },
+		],
+	},
 	"gpt-5-mini-2025-08-07": {
 		maxTokens: 128000,
 		contextWindow: 400000,

src/api/index.ts

@@ -10,6 +10,7 @@ import {
 	AwsBedrockHandler,
 	CerebrasHandler,
 	OpenRouterHandler,
+	CodexHandler,
 	VertexHandler,
 	AnthropicVertexHandler,
 	OpenAiHandler,
@@ -121,6 +122,8 @@ export function buildApiHandler(configuration: ProviderSettings): ApiHandler {
 			return new DoubaoHandler(options)
 		case "qwen-code":
 			return new QwenCodeHandler(options)
+		case "codex":
+			return new CodexHandler(options)
 		case "moonshot":
 			return new MoonshotHandler(options)
 		case "vscode-lm":

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

@@ -1,4 +1,5 @@
 import { describe, it, expect, beforeEach, afterEach, vi } from "vitest"
+import type { MockInstance } from "vitest"
 import type { Anthropic } from "@anthropic-ai/sdk"
 
 import type { ApiStreamChunk } from "../../transform/stream"
@@ -53,11 +54,17 @@ function asyncGeneratorFromChunks(chunks: ApiStreamChunk[]): AsyncGenerator<ApiS
 
 describe("CodexHandler", () => {
 	let handler: CodexHandler
-	let fallbackSpy: ReturnType<typeof vi.spyOn>
+	let fallbackSpy: MockInstance<typeof OpenAiNativeHandler.prototype.createMessage>
 
 	beforeEach(() => {
 		createSessionMock.mockReset()
-		fallbackSpy = vi.spyOn(OpenAiNativeHandler.prototype, "createMessage").mockImplementation(async function* () {
+		fallbackSpy = vi.spyOn(OpenAiNativeHandler.prototype, "createMessage")
+		fallbackSpy.mockImplementation(async function* (
+			this: OpenAiNativeHandler,
+			_systemPrompt: string,
+			_messages: Anthropic.Messages.MessageParam[],
+			_metadata?: ApiHandlerCreateMessageMetadata,
+		) {
 			yield { type: "text", text: "[fallback]" }
 		})
 		handler = new CodexHandler(defaultOptions)

src/api/providers/index.ts

@@ -21,6 +21,7 @@ export { OllamaHandler } from "./ollama"
 export { OpenAiNativeHandler } from "./openai-native"
 export { OpenAiHandler } from "./openai"
 export { OpenRouterHandler } from "./openrouter"
+export { CodexHandler } from "./codex"
 export { QwenCodeHandler } from "./qwen-code"
 export { RequestyHandler } from "./requesty"
 export { SambaNovaHandler } from "./sambanova"