What happens when a tool throws an error?

[abaybektursun]

I have tools that are throwing errors, for example

Throw new Error(`Failed to fetch contacts: ${response.statusText}`)

However, they are completely suppressed. What can I do to enable the error traces in Tool calling?

[remorses]

I faced the same issue, this is a big in my opinion @lgrammel

Errors thrown in tools are completely suppressed and don’t show any logs

[lgrammel]

Can you be more specific on how you use your tools?

When you throw errors in tools, they get wrapped in a ToolExecutionError, and that gets raised differently depending which function you use and how.

https://sdk.vercel.ai/docs/reference/ai-sdk-errors/ai-tool-execution-error

[remorses]

Here is an example, the error was getting completely suppressed, then noticed there are chunks of type error you can listen for.

In my opinion streamText should log something when an error happens in a tool, you use .fullStream and chunk.error is not accessed.

import { anthropic } from '@ai-sdk/anthropic'
import { streamText, tool } from 'ai'
import { test } from 'vitest'
import { z } from 'zod'

test('ai tools throw errors', async () => {
    const res = streamText({
        model: anthropic('claude-3-5-haiku-latest'),
        tools: {
            hello: tool({
                parameters: z.object({
                    name: z.string(),
                }),

                async execute({ name }) {
                    console.log('called hello with', name)
                    throw new Error('hello error')
                },
            }),
        },
        prompt: `first decide on what my name should be, then call the tool hello with the chosen name`,
    })
    for await (let chunk of res.fullStream) {
        if (chunk.type === 'text-delta') {
            process.stdout.write(chunk.textDelta)
        }
        if (chunk.type === 'tool-call') {
            process.stdout.write(JSON.stringify(chunk.toolCallId))
        }
        if (chunk.type === 'error') {
            console.log('error', chunk.error)
        }
    }
})