Tool system

User message
     │
     ▼
QueryEngine sends message to Anthropic API
     │
     ▼
Claude returns a tool_use block (tool name + input)
     │
     ▼
Permission layer checks the call
     │ allowed
     ▼
Tool validates input with Zod schema
     │
     ▼
Tool executes and returns a result
     │
     ▼
Result is appended as tool_result and sent back to Claude
     │
     ▼
Claude continues (may call more tools or return final response)

import { z } from 'zod/v4'

const inputSchema = z.object({
  path: z.string().describe('Absolute path to the file'),
  limit: z.number().optional().describe('Maximum lines to return'),
})

async execute(input, context) {
  const content = await fs.readFile(input.path, 'utf8')
  return { type: 'text', text: content }
}

// Always registered
import { FileReadTool } from './tools/FileReadTool/FileReadTool.js'
import { BashTool } from './tools/BashTool/BashTool.js'

// Only registered when the PROACTIVE flag is enabled at build time
const SleepTool = feature('PROACTIVE') || feature('KAIROS')
  ? require('./tools/SleepTool/SleepTool.js').SleepTool
  : null

// Only for internal Anthropic users
const REPLTool = process.env.USER_TYPE === 'ant'
  ? require('./tools/REPLTool/REPLTool.js').REPLTool
  : null