jan/extensions/assistant-extension/src/index.ts

import { Assistant, AssistantExtension, fs, joinPath } from '@janhq/core'
export default class JanAssistantExtension extends AssistantExtension {
  async onLoad() {
    if (!(await fs.existsSync('file://assistants'))) {
      await fs.mkdir('file://assistants')
    }
    const assistants = await this.getAssistants()
    if (assistants.length === 0) {
      await this.createAssistant(this.defaultAssistant)
    }
  }

  /**
   * Called when the extension is unloaded.
   */
  onUnload(): void {}

  async getAssistants(): Promise<Assistant[]> {
    if (!(await fs.existsSync('file://assistants')))
      return [this.defaultAssistant]
    const assistants = await fs.readdirSync('file://assistants')
    const assistantsData: Assistant[] = []
    for (const assistant of assistants) {
      const assistantPath = await joinPath([
        'file://assistants',
        assistant,
        'assistant.json',
      ])
      if (!(await fs.existsSync(assistantPath))) {
        console.warn(`Assistant file not found: ${assistantPath}`)
        continue
      }
      try {
        const assistantData = JSON.parse(await fs.readFileSync(assistantPath))
        assistantsData.push(assistantData as Assistant)
      } catch (error) {
        console.error(`Failed to read assistant ${assistant}:`, error)
      }
    }
    return assistantsData
  }

  async createAssistant(assistant: Assistant): Promise<void> {
    const assistantPath = await joinPath([
      'file://assistants',
      assistant.id,
      'assistant.json',
    ])
    const assistantFolder = await joinPath(['file://assistants', assistant.id])
    if (!(await fs.existsSync(assistantFolder))) {
      await fs.mkdir(assistantFolder)
    }
    await fs.writeFileSync(assistantPath, JSON.stringify(assistant, null, 2))
  }

  async deleteAssistant(assistant: Assistant): Promise<void> {
    const assistantPath = await joinPath([
      'file://assistants',
      assistant.id,
      'assistant.json',
    ])
    if (await fs.existsSync(assistantPath)) {
      await fs.rm(assistantPath)
    }
  }

  private defaultAssistant: Assistant = {
    avatar: '👋',
    thread_location: undefined,
    id: 'jan',
    object: 'assistant',
    created_at: Date.now() / 1000,
    name: 'Jan',
    description:
      'Jan is a helpful desktop assistant that can reason through complex tasks and use tools to complete them on the user’s behalf.',
    model: '*',
    instructions:
      'You have access to a set of tools to help you answer the user’s question. You can use only one tool per message, and you’ll receive the result of that tool in the user’s next response. To complete a task, use tools step by step—each step should be guided by the outcome of the previous one.\nTool Usage Rules:\n1. Always provide the correct values as arguments when using tools. Do not pass variable names—use actual values instead.\n2. You may perform multiple tool steps to complete a task.\n3. Avoid repeating a tool call with exactly the same parameters to prevent infinite loops.',
    tools: [
      {
        type: 'retrieval',
        enabled: false,
        useTimeWeightedRetriever: false,
        settings: {
          top_k: 2,
          chunk_size: 1024,
          chunk_overlap: 64,
          retrieval_template: `Use the following pieces of context to answer the question at the end.
----------------
CONTEXT: {CONTEXT}
----------------
QUESTION: {QUESTION}
----------------
Helpful Answer:`,
        },
      },
    ],
    file_ids: [],
    metadata: undefined,
  }
}