Authoring Tools

Tools give your agent the ability to take actions. Define them in two styles.

Flue-native tools

// src/tools/search.ts
import { tool } from '@flue/runtime'

export default tool({
  name: 'search',
  description: 'Search the web',
  parameters: {
    type: 'object',
    properties: {
      query: { type: 'string' },
    },
    required: ['query'],
  },
  execute: async ({ query }) => {
    return await searchWeb(query)
  },
})

import { createAgent } from '@flue/runtime'
import searchTool from './tools/search'

export default createAgent({
  model: 'anthropic/claude-sonnet-4-6',
  tools: [searchTool],
})

Eve-style (declarative)

Place tool files in agent/tools/:

// agent/tools/get-weather.ts
export default {
  name: "get_weather",
  description: "Get weather for a city",
  parameters: {
    type: "object",
    properties: { city: { type: "string" } },
    required: ["city"],
  },
  execute: async ({ city }) => ({ city, temp: 72, condition: "sunny" }),
}

Run npx flue-eve init to generate Flue tool adapters from these declarations.

Tool schema

Both styles produce the same runtime shape:

Field	Type	Required
`name`	`string`	Yes
`description`	`string`	Yes
`parameters`	JSON Schema	Yes
`execute`	`async function`	Yes

See authoring model for how these two styles relate, and connections guide for defining MCP connections.