feat: add direct DeepSeek API support for V3/3.2 models

- Add model aliases (deepseek-v3, deepseek-3.2) that map to deepseek-chat
- Update DeepSeek handler to map alias model names to official API model names
- Add tests to verify model alias mapping works correctly
- Supports DeepSeek 3.2 models as requested in issue #9779

packages/types/src/providers/deepseek.ts

@@ -1,22 +1,35 @@
 import type { ModelInfo } from "../model.js"
 
 // https://platform.deepseek.com/docs/api
+// https://api-docs.deepseek.com/quick_start/pricing
 export type DeepSeekModelId = keyof typeof deepSeekModels
 
 export const deepSeekDefaultModelId: DeepSeekModelId = "deepseek-chat"
 
+// DeepSeek V3 model info (shared between deepseek-chat and aliases)
+const deepSeekV3Info: ModelInfo = {
+	maxTokens: 8192, // 8K max output
+	contextWindow: 128_000,
+	supportsImages: false,
+	supportsPromptCache: true,
+	supportsNativeTools: true,
+	inputPrice: 0.56, // $0.56 per million tokens (cache miss) - Updated Sept 5, 2025
+	outputPrice: 1.68, // $1.68 per million tokens - Updated Sept 5, 2025
+	cacheWritesPrice: 0.56, // $0.56 per million tokens (cache miss) - Updated Sept 5, 2025
+	cacheReadsPrice: 0.07, // $0.07 per million tokens (cache hit) - Updated Sept 5, 2025
+	description: `DeepSeek-V3 achieves a significant breakthrough in inference speed over previous models. It tops the leaderboard among open-source models and rivals the most advanced closed-source models globally.`,
+}
+
 export const deepSeekModels = {
-	"deepseek-chat": {
-		maxTokens: 8192, // 8K max output
-		contextWindow: 128_000,
-		supportsImages: false,
-		supportsPromptCache: true,
-		supportsNativeTools: true,
-		inputPrice: 0.56, // $0.56 per million tokens (cache miss) - Updated Sept 5, 2025
-		outputPrice: 1.68, // $1.68 per million tokens - Updated Sept 5, 2025
-		cacheWritesPrice: 0.56, // $0.56 per million tokens (cache miss) - Updated Sept 5, 2025
-		cacheReadsPrice: 0.07, // $0.07 per million tokens (cache hit) - Updated Sept 5, 2025
-		description: `DeepSeek-V3 achieves a significant breakthrough in inference speed over previous models. It tops the leaderboard among open-source models and rivals the most advanced closed-source models globally.`,
+	"deepseek-chat": deepSeekV3Info,
+	// Aliases for DeepSeek V3 - these all map to deepseek-chat when calling the API
+	"deepseek-v3": {
+		...deepSeekV3Info,
+		description: `DeepSeek-V3 (alias for deepseek-chat). ${deepSeekV3Info.description}`,
+	},
+	"deepseek-3.2": {
+		...deepSeekV3Info,
+		description: `DeepSeek V3.2 (alias for deepseek-chat). ${deepSeekV3Info.description}`,
 	},
 	"deepseek-reasoner": {
 		maxTokens: 65536, // 64K max output for reasoning mode
@@ -32,4 +45,12 @@ export const deepSeekModels = {
 	},
 } as const satisfies Record<string, ModelInfo>
 
+// Map of model aliases to their official API model names
+// The DeepSeek API uses specific model names, but users may use alternative names
+export const deepSeekModelAliases: Record<string, string> = {
+	"deepseek-v3": "deepseek-chat",
+	"deepseek-3.2": "deepseek-chat",
+	"deepseek-3.2-exp": "deepseek-chat",
+}
+
 export const DEEP_SEEK_DEFAULT_TEMPERATURE = 0.6

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

@@ -147,6 +147,44 @@ describe("DeepSeekHandler", () => {
 			const _handler = new DeepSeekHandler(mockOptions)
 			expect(OpenAI).toHaveBeenCalledWith(expect.objectContaining({ apiKey: mockOptions.deepSeekApiKey }))
 		})
+
+		it("should map deepseek-v3 alias to deepseek-chat for API calls", async () => {
+			vi.clearAllMocks()
+			const handlerWithV3 = new DeepSeekHandler({
+				...mockOptions,
+				apiModelId: "deepseek-v3",
+			})
+			const stream = handlerWithV3.createMessage("test", [])
+			for await (const _chunk of stream) {
+				// consume stream
+			}
+			// Verify the API was called with deepseek-chat (not deepseek-v3)
+			expect(mockCreate).toHaveBeenCalledWith(
+				expect.objectContaining({
+					model: "deepseek-chat",
+				}),
+				expect.anything(),
+			)
+		})
+
+		it("should map deepseek-3.2 alias to deepseek-chat for API calls", async () => {
+			vi.clearAllMocks()
+			const handlerWith32 = new DeepSeekHandler({
+				...mockOptions,
+				apiModelId: "deepseek-3.2",
+			})
+			const stream = handlerWith32.createMessage("test", [])
+			for await (const _chunk of stream) {
+				// consume stream
+			}
+			// Verify the API was called with deepseek-chat (not deepseek-3.2)
+			expect(mockCreate).toHaveBeenCalledWith(
+				expect.objectContaining({
+					model: "deepseek-chat",
+				}),
+				expect.anything(),
+			)
+		})
 	})
 
 	describe("getModel", () => {
@@ -174,6 +212,32 @@ describe("DeepSeekHandler", () => {
 			expect(model.info.supportsPromptCache).toBe(true)
 		})
 
+		it("should return correct model info for deepseek-v3 alias", () => {
+			const handlerWithV3 = new DeepSeekHandler({
+				...mockOptions,
+				apiModelId: "deepseek-v3",
+			})
+			const model = handlerWithV3.getModel()
+			expect(model.id).toBe("deepseek-v3") // Returns user's model ID
+			expect(model.info).toBeDefined()
+			expect(model.info.maxTokens).toBe(8192) // Same as deepseek-chat
+			expect(model.info.contextWindow).toBe(128_000)
+			expect(model.info.supportsNativeTools).toBe(true)
+		})
+
+		it("should return correct model info for deepseek-3.2 alias", () => {
+			const handlerWith32 = new DeepSeekHandler({
+				...mockOptions,
+				apiModelId: "deepseek-3.2",
+			})
+			const model = handlerWith32.getModel()
+			expect(model.id).toBe("deepseek-3.2") // Returns user's model ID
+			expect(model.info).toBeDefined()
+			expect(model.info.maxTokens).toBe(8192) // Same as deepseek-chat
+			expect(model.info.contextWindow).toBe(128_000)
+			expect(model.info.supportsNativeTools).toBe(true)
+		})
+
 		it("should return provided model ID with default model info if model does not exist", () => {
 			const handlerWithInvalidModel = new DeepSeekHandler({
 				...mockOptions,

src/api/providers/deepseek.ts

@@ -1,4 +1,4 @@
-import { deepSeekModels, deepSeekDefaultModelId } from "@roo-code/types"
+import { deepSeekModels, deepSeekDefaultModelId, deepSeekModelAliases } from "@roo-code/types"
 
 import type { ApiHandlerOptions } from "../../shared/api"
 
@@ -7,20 +7,40 @@ import { getModelParams } from "../transform/model-params"
 
 import { OpenAiHandler } from "./openai"
 
+/**
+ * Maps a user-provided model ID to the official DeepSeek API model name.
+ * The DeepSeek API uses specific model names (deepseek-chat, deepseek-reasoner),
+ * but users may use alternative names like deepseek-v3, deepseek-3.2, etc.
+ */
+function getApiModelId(modelId: string): string {
+	return deepSeekModelAliases[modelId] ?? modelId
+}
+
 export class DeepSeekHandler extends OpenAiHandler {
 	constructor(options: ApiHandlerOptions) {
+		const userModelId = options.apiModelId ?? deepSeekDefaultModelId
+		// Map the user's model ID to the official API model name
+		const apiModelId = getApiModelId(userModelId)
+
 		super({
 			...options,
 			openAiApiKey: options.deepSeekApiKey ?? "not-provided",
-			openAiModelId: options.apiModelId ?? deepSeekDefaultModelId,
+			openAiModelId: apiModelId, // Use the mapped API model ID
 			openAiBaseUrl: options.deepSeekBaseUrl ?? "https://api.deepseek.com",
 			openAiStreamingEnabled: true,
 			includeMaxTokens: true,
 		})
+
+		// Store the original user model ID for getModel()
+		this.userModelId = userModelId
 	}
 
+	// Store the user's original model ID (before alias mapping)
+	private userModelId: string
+
 	override getModel() {
-		const id = this.options.apiModelId ?? deepSeekDefaultModelId
+		// Use the user's original model ID for info lookup (so they see the model they selected)
+		const id = this.userModelId
 		const info = deepSeekModels[id as keyof typeof deepSeekModels] || deepSeekModels[deepSeekDefaultModelId]
 		const params = getModelParams({ format: "openai", modelId: id, model: info, settings: this.options })
 		return { id, info, ...params }