Add Mistral API provider

src/api/index.ts

@@ -11,6 +11,7 @@ import { LmStudioHandler } from "./providers/lmstudio"
 import { GeminiHandler } from "./providers/gemini"
 import { OpenAiNativeHandler } from "./providers/openai-native"
 import { DeepSeekHandler } from "./providers/deepseek"
+import { MistralHandler } from "./providers/mistral"
 import { VsCodeLmHandler } from "./providers/vscode-lm"
 import { ApiStream } from "./transform/stream"
 
@@ -50,6 +51,8 @@ export function buildApiHandler(configuration: ApiConfiguration): ApiHandler {
 			return new DeepSeekHandler(options)
 		case "vscode-lm":
 			return new VsCodeLmHandler(options)
+		case "mistral":
+			return new MistralHandler(options)
 		default:
 			return new AnthropicHandler(options)
 	}

src/api/providers/mistral.ts

@@ -0,0 +1,74 @@
+import { Anthropic } from "@anthropic-ai/sdk"
+import { Mistral } from "@mistralai/mistralai"
+import { ApiHandler } from "../"
+import {
+	ApiHandlerOptions,
+	mistralDefaultModelId,
+	MistralModelId,
+	mistralModels,
+	ModelInfo,
+	openAiNativeDefaultModelId,
+	OpenAiNativeModelId,
+	openAiNativeModels,
+} from "../../shared/api"
+import { convertToMistralMessages } from "../transform/mistral-format"
+import { ApiStream } from "../transform/stream"
+
+export class MistralHandler implements ApiHandler {
+	private options: ApiHandlerOptions
+	private client: Mistral
+
+	constructor(options: ApiHandlerOptions) {
+		this.options = options
+		this.client = new Mistral({
+			serverURL: "https://codestral.mistral.ai",
+			apiKey: this.options.mistralApiKey,
+		})
+	}
+
+	async *createMessage(systemPrompt: string, messages: Anthropic.Messages.MessageParam[]): ApiStream {
+		const stream = await this.client.chat.stream({
+			model: this.getModel().id,
+			// max_completion_tokens: this.getModel().info.maxTokens,
+			temperature: 0,
+			messages: [{ role: "system", content: systemPrompt }, ...convertToMistralMessages(messages)],
+			stream: true,
+		})
+
+		for await (const chunk of stream) {
+			const delta = chunk.data.choices[0]?.delta
+			if (delta?.content) {
+				let content: string = ""
+				if (typeof delta.content === "string") {
+					content = delta.content
+				} else if (Array.isArray(delta.content)) {
+					content = delta.content.map((c) => (c.type === "text" ? c.text : "")).join("")
+				}
+				yield {
+					type: "text",
+					text: content,
+				}
+			}
+
+			if (chunk.data.usage) {
+				yield {
+					type: "usage",
+					inputTokens: chunk.data.usage.promptTokens || 0,
+					outputTokens: chunk.data.usage.completionTokens || 0,
+				}
+			}
+		}
+	}
+
+	getModel(): { id: MistralModelId; info: ModelInfo } {
+		const modelId = this.options.apiModelId
+		if (modelId && modelId in mistralModels) {
+			const id = modelId as MistralModelId
+			return { id, info: mistralModels[id] }
+		}
+		return {
+			id: mistralDefaultModelId,
+			info: mistralModels[mistralDefaultModelId],
+		}
+	}
+}

src/api/transform/mistral-format.ts

@@ -0,0 +1,92 @@
+import { Anthropic } from "@anthropic-ai/sdk"
+import { Mistral } from "@mistralai/mistralai"
+import { AssistantMessage } from "@mistralai/mistralai/models/components/assistantmessage"
+import { SystemMessage } from "@mistralai/mistralai/models/components/systemmessage"
+import { ToolMessage } from "@mistralai/mistralai/models/components/toolmessage"
+import { UserMessage } from "@mistralai/mistralai/models/components/usermessage"
+
+export type MistralMessage =
+	| (SystemMessage & { role: "system" })
+	| (UserMessage & { role: "user" })
+	| (AssistantMessage & { role: "assistant" })
+	| (ToolMessage & { role: "tool" })
+
+export function convertToMistralMessages(anthropicMessages: Anthropic.Messages.MessageParam[]): MistralMessage[] {
+	const mistralMessages: MistralMessage[] = []
+	for (const anthropicMessage of anthropicMessages) {
+		if (typeof anthropicMessage.content === "string") {
+			mistralMessages.push({
+				role: anthropicMessage.role,
+				content: anthropicMessage.content,
+			})
+		} else {
+			if (anthropicMessage.role === "user") {
+				const { nonToolMessages, toolMessages } = anthropicMessage.content.reduce<{
+					nonToolMessages: (Anthropic.TextBlockParam | Anthropic.ImageBlockParam)[]
+					toolMessages: Anthropic.ToolResultBlockParam[]
+				}>(
+					(acc, part) => {
+						if (part.type === "tool_result") {
+							acc.toolMessages.push(part)
+						} else if (part.type === "text" || part.type === "image") {
+							acc.nonToolMessages.push(part)
+						} // user cannot send tool_use messages
+						return acc
+					},
+					{ nonToolMessages: [], toolMessages: [] },
+				)
+
+				if (nonToolMessages.length > 0) {
+					mistralMessages.push({
+						role: "user",
+						content: nonToolMessages.map((part) => {
+							if (part.type === "image") {
+								return {
+									type: "image_url",
+									imageUrl: {
+										url: `data:${part.source.media_type};base64,${part.source.data}`,
+									},
+								}
+							}
+							return { type: "text", text: part.text }
+						}),
+					})
+				}
+			} else if (anthropicMessage.role === "assistant") {
+				const { nonToolMessages, toolMessages } = anthropicMessage.content.reduce<{
+					nonToolMessages: (Anthropic.TextBlockParam | Anthropic.ImageBlockParam)[]
+					toolMessages: Anthropic.ToolUseBlockParam[]
+				}>(
+					(acc, part) => {
+						if (part.type === "tool_use") {
+							acc.toolMessages.push(part)
+						} else if (part.type === "text" || part.type === "image") {
+							acc.nonToolMessages.push(part)
+						} // assistant cannot send tool_result messages
+						return acc
+					},
+					{ nonToolMessages: [], toolMessages: [] },
+				)
+
+				let content: string | undefined
+				if (nonToolMessages.length > 0) {
+					content = nonToolMessages
+						.map((part) => {
+							if (part.type === "image") {
+								return "" // impossible as the assistant cannot send images
+							}
+							return part.text
+						})
+						.join("\n")
+				}
+
+				mistralMessages.push({
+					role: "assistant",
+					content,
+				})
+			}
+		}
+	}
+
+	return mistralMessages
+}