Files
page-agent/packages/page-agent/src/PageAgent.ts
2025-12-15 09:52:23 +00:00

519 lines
14 KiB
TypeScript

/**
* Copyright (C) 2025 Alibaba Group Holding Limited
* All rights reserved.
*/
import { PageController } from '@page-agent/page-controller'
import { Panel, SimulatorMask } from '@page-agent/ui'
import chalk from 'chalk'
import zod from 'zod'
import type { PageAgentConfig } from './config'
import { MAX_STEPS } from './config/constants'
import { LLM, type Tool } from './llms'
import SYSTEM_PROMPT from './prompts/system_prompt.md?raw'
import { tools } from './tools'
import { trimLines, uid, waitUntil } from './utils'
import { assert } from './utils/assert'
export type { PageAgentConfig }
export { tool, type PageAgentTool } from './tools'
export interface AgentBrain {
// thinking?: string
evaluation_previous_goal: string
memory: string
next_goal: string
}
/**
* MacroTool input structure
*/
export interface MacroToolInput {
evaluation_previous_goal?: string
memory?: string
next_goal?: string
action: Record<string, any>
}
/**
* MacroTool output structure
*/
export interface MacroToolResult {
input: MacroToolInput
output: string
}
export interface AgentHistory {
brain: AgentBrain
action: {
name: string
input: any
output: string
}
usage: {
promptTokens: number
completionTokens: number
totalTokens: number
cachedTokens?: number
reasoningTokens?: number
}
}
export interface ExecutionResult {
success: boolean
data: string
history: AgentHistory[]
}
export class PageAgent extends EventTarget {
config: PageAgentConfig
id = uid()
panel: Panel
tools: typeof tools
paused = false
disposed = false
task = ''
taskId = ''
#llm: LLM
#totalWaitTime = 0
#abortController = new AbortController()
#llmRetryListener: ((e: Event) => void) | null = null
#llmErrorListener: ((e: Event) => void) | null = null
#beforeUnloadListener: ((e: Event) => void) | null = null
/** PageController for DOM operations */
pageController: PageController
/** Fullscreen mask */
mask = new SimulatorMask()
/** History records */
history: AgentHistory[] = []
constructor(config: PageAgentConfig = {}) {
super()
this.config = config
this.#llm = new LLM(this.config)
this.panel = new Panel({
language: this.config.language,
onExecuteTask: (task) => this.execute(task),
onStop: () => this.dispose(),
onPauseToggle: () => {
this.paused = !this.paused
return this.paused
},
getPaused: () => this.paused,
})
this.tools = new Map(tools)
// Initialize PageController with config
this.pageController = new PageController(this.config)
// Listen to LLM events
this.#llmRetryListener = (e) => {
const { current, max } = (e as CustomEvent).detail
this.panel.update({ type: 'retry', current, max })
}
this.#llmErrorListener = (e) => {
const { error } = (e as CustomEvent).detail
this.panel.update({ type: 'error', message: `step failed: ${error.message}` })
}
this.#llm.addEventListener('retry', this.#llmRetryListener)
this.#llm.addEventListener('error', this.#llmErrorListener)
if (this.config.customTools) {
for (const [name, tool] of Object.entries(this.config.customTools)) {
if (tool === null) {
this.tools.delete(name)
continue
}
this.tools.set(name, tool)
}
}
if (!this.config.experimentalScriptExecutionTool) {
this.tools.delete('execute_javascript')
}
this.#beforeUnloadListener = (e) => {
if (!this.disposed) this.dispose('PAGE_UNLOADING')
}
window.addEventListener('beforeunload', this.#beforeUnloadListener)
}
/**
* @todo maybe return something?
*/
async execute(task: string): Promise<ExecutionResult> {
if (!task) throw new Error('Task is required')
this.task = task
this.taskId = uid()
const onBeforeStep = this.config.onBeforeStep || (() => void 0)
const onAfterStep = this.config.onAfterStep || (() => void 0)
const onBeforeTask = this.config.onBeforeTask || (() => void 0)
const onAfterTask = this.config.onAfterTask || (() => void 0)
await onBeforeTask.call(this)
// Show mask and panel
this.mask.show()
this.panel.show()
this.panel.reset()
this.panel.update({ type: 'input', task: this.task })
if (this.#abortController) {
this.#abortController.abort()
this.#abortController = new AbortController()
}
this.history = []
try {
let step = 0
while (true) {
await onBeforeStep.call(this, step)
console.group(`step: ${step}`)
// abort
if (this.#abortController.signal.aborted) throw new Error('AbortError')
// pause
await waitUntil(() => !this.paused)
// Update status to thinking
console.log(chalk.blue('Thinking...'))
this.panel.update({ type: 'thinking' })
const result = await this.#llm.invoke(
[
{
role: 'system',
content: this.#getSystemPrompt(),
},
{
role: 'user',
content: await this.#assembleUserPrompt(),
},
],
{ AgentOutput: this.#packMacroTool() },
this.#abortController.signal
)
const macroResult = result.toolResult as MacroToolResult
const input = macroResult.input
const output = macroResult.output
const brain = {
evaluation_previous_goal: input.evaluation_previous_goal || '',
memory: input.memory || '',
next_goal: input.next_goal || '',
}
const actionName = Object.keys(input.action)[0]
const action = {
name: actionName,
input: input.action[actionName],
output: output,
}
this.history.push({
brain,
action,
usage: result.usage,
})
console.log(chalk.green('Step finished:'), actionName)
console.groupEnd()
await onAfterStep.call(this, step, this.history)
step++
if (step > MAX_STEPS) {
this.#onDone('Step count exceeded maximum limit', false)
const result: ExecutionResult = {
success: false,
data: 'Step count exceeded maximum limit',
history: this.history,
}
await onAfterTask.call(this, result)
return result
}
if (actionName === 'done') {
const success = action.input?.success ?? false
const text = action.input?.text || 'no text provided'
console.log(chalk.green.bold('Task completed'), success, text)
this.#onDone(text, success)
const result: ExecutionResult = {
success,
data: text,
history: this.history,
}
await onAfterTask.call(this, result)
return result
}
}
} catch (error: unknown) {
console.error('Task failed', error)
this.#onDone(String(error), false)
const result: ExecutionResult = {
success: false,
data: String(error),
history: this.history,
}
await onAfterTask.call(this, result)
return result
}
}
/**
* Merge all tools into a single MacroTool with the following input:
* - thinking: string
* - evaluation_previous_goal: string
* - memory: string
* - next_goal: string
* - action: { toolName: toolInput }
* where action must be selected from tools defined in this.tools
*/
#packMacroTool(): Tool<MacroToolInput, MacroToolResult> {
const tools = this.tools
const actionSchemas = Array.from(tools.entries()).map(([toolName, tool]) => {
return zod.object({
[toolName]: tool.inputSchema,
})
})
const actionSchema = zod.union(
actionSchemas as unknown as [zod.ZodType, zod.ZodType, ...zod.ZodType[]]
)
const macroToolSchema = zod.object({
// thinking: zod.string().optional(),
evaluation_previous_goal: zod.string().optional(),
memory: zod.string().optional(),
next_goal: zod.string().optional(),
action: actionSchema,
})
return {
inputSchema: macroToolSchema as zod.ZodType<MacroToolInput>,
execute: async (input: MacroToolInput): Promise<MacroToolResult> => {
// abort
if (this.#abortController.signal.aborted) throw new Error('AbortError')
// pause
await waitUntil(() => !this.paused)
console.log(chalk.blue.bold('MacroTool execute'), input)
const action = input.action
const toolName = Object.keys(action)[0]
const toolInput = action[toolName]
const brain = trimLines(`✅: ${input.evaluation_previous_goal}
💾: ${input.memory}
🎯: ${input.next_goal}
`)
console.log(brain)
this.panel.update({ type: 'thinking', text: brain })
// Find the corresponding tool
const tool = tools.get(toolName)
assert(tool, `Tool ${toolName} not found. (@note should have been caught before this!!!)`)
console.log(chalk.blue.bold(`Executing tool: ${toolName}`), toolInput)
this.panel.update({ type: 'toolExecuting', toolName, args: toolInput })
const startTime = Date.now()
// Execute tool, bind `this` to PageAgent
let result = await tool.execute.bind(this)(toolInput)
const duration = Date.now() - startTime
console.log(chalk.green.bold(`Tool (${toolName}) executed for ${duration}ms`), result)
if (toolName === 'wait') {
this.#totalWaitTime += Math.round(toolInput.seconds + duration / 1000)
result += `\n<sys> You have waited ${this.#totalWaitTime} seconds accumulatively.`
if (this.#totalWaitTime >= 3)
result += '\nDo NOT wait any longer unless you have a good reason.\n'
result += '</sys>'
} else {
// For other tools, reset wait time
this.#totalWaitTime = 0
}
// Briefly display execution result
this.panel.update({
type: 'toolCompleted',
toolName,
args: toolInput,
result,
duration,
})
// Wait a moment to let user see the result
await new Promise((resolve) => setTimeout(resolve, 100))
// Return structured result
return {
input,
output: result,
}
},
}
}
/**
* Get system prompt, dynamically replace language settings based on configured language
*/
#getSystemPrompt(): string {
let systemPrompt = SYSTEM_PROMPT
const targetLanguage = this.config.language === 'zh-CN' ? '中文' : 'English'
systemPrompt = systemPrompt.replace(
/Default working language: \*\*.*?\*\*/,
`Default working language: **${targetLanguage}**`
)
return systemPrompt
}
async #assembleUserPrompt(): Promise<string> {
let prompt = ''
// <agent_history>
// - <step_>
prompt += '<agent_history>\n'
this.history.forEach((history, index) => {
prompt += `<step_${index + 1}>
Evaluation of Previous Step: ${history.brain.evaluation_previous_goal}
Memory: ${history.brain.memory}
Next Goal: ${history.brain.next_goal}
Action Results: ${history.action.output}
</step_${index + 1}>
`
})
prompt += '</agent_history>\n\n'
// <agent_state>
// - <user_request>
// - <step_info>
// <agent_state>
prompt += `<agent_state>
<user_request>
${this.task}
</user_request>
<step_info>
Step ${this.history.length + 1} of ${MAX_STEPS} max possible steps
Current date and time: ${new Date().toISOString()}
</step_info>
</agent_state>
`
// <browser_state>
prompt += await this.#getBrowserState()
return trimLines(prompt)
}
#onDone(text: string, success = true) {
this.pageController.cleanUpHighlights()
// Update panel status
if (success) {
this.panel.update({ type: 'output', text })
} else {
this.panel.update({ type: 'error', message: text })
}
// Task completed
this.panel.update({ type: 'completed' })
this.mask.hide()
this.#abortController.abort()
}
async #getBrowserState(): Promise<string> {
const pageUrl = await this.pageController.getCurrentUrl()
const pageTitle = await this.pageController.getPageTitle()
const pi = await this.pageController.getPageInfo()
const viewportExpansion = await this.pageController.getViewportExpansion()
this.mask.wrapper.style.pointerEvents = 'none'
await this.pageController.updateTree()
this.mask.wrapper.style.pointerEvents = 'auto'
const simplifiedHTML = await this.pageController.getSimplifiedHTML()
let prompt = trimLines(`<browser_state>
Current Page: [${pageTitle}](${pageUrl})
Page info: ${pi.viewport_width}x${pi.viewport_height}px viewport, ${pi.page_width}x${pi.page_height}px total page size, ${pi.pages_above.toFixed(1)} pages above, ${pi.pages_below.toFixed(1)} pages below, ${pi.total_pages.toFixed(1)} total pages, at ${(pi.current_page_position * 100).toFixed(0)}% of page
${viewportExpansion === -1 ? 'Interactive elements from top layer of the current page (full page):' : 'Interactive elements from top layer of the current page inside the viewport:'}
`)
// Page header info
const has_content_above = pi.pixels_above > 4
if (has_content_above && viewportExpansion !== -1) {
prompt += `... ${pi.pixels_above} pixels above (${pi.pages_above.toFixed(1)} pages) - scroll to see more ...\n`
} else {
prompt += `[Start of page]\n`
}
// Current viewport info
prompt += simplifiedHTML
prompt += `\n`
// Page footer info
const has_content_below = pi.pixels_below > 4
if (has_content_below && viewportExpansion !== -1) {
prompt += `... ${pi.pixels_below} pixels below (${pi.pages_below.toFixed(1)} pages) - scroll to see more ...\n`
} else {
prompt += `[End of page]\n`
}
prompt += `</browser_state>\n`
return prompt
}
dispose(reason?: string) {
console.log('Disposing PageAgent...')
this.disposed = true
this.pageController.dispose()
this.panel.dispose()
this.mask.dispose()
this.history = []
this.#abortController.abort(reason ?? 'PageAgent disposed')
// Clean up LLM event listeners
if (this.#llmRetryListener) {
this.#llm.removeEventListener('retry', this.#llmRetryListener)
this.#llmRetryListener = null
}
if (this.#llmErrorListener) {
this.#llm.removeEventListener('error', this.#llmErrorListener)
this.#llmErrorListener = null
}
// Clean up window event listeners
if (this.#beforeUnloadListener) {
window.removeEventListener('beforeunload', this.#beforeUnloadListener)
this.#beforeUnloadListener = null
}
this.config.onDispose?.call(this, reason)
}
}