DevTools

AI SDK DevTools gives you full visibility over your AI SDK calls with generateText, streamText, and ToolLoopAgent. It helps you debug and inspect LLM requests, responses, tool calls, and multi-step interactions through a web-based UI.

DevTools is composed of two parts:

1. Middleware: Captures runs and steps from your AI SDK calls
2. Viewer: A web UI to inspect the captured data

Installation

Install the DevTools package:

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pnpm add @ai-sdk/devtools

Requirements

• AI SDK v6 beta (ai@^6.0.0-beta.0)
• Node.js compatible runtime

Using DevTools

Add the middleware

Wrap your language model with the DevTools middleware using wrapLanguageModel:

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import { wrapLanguageModel } from 'ai';
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import { devToolsMiddleware } from '@ai-sdk/devtools';
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const model = wrapLanguageModel({
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  model: "anthropic/claude-sonnet-4.5",
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  middleware: devToolsMiddleware,
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});

The wrapped model can be used with any AI SDK Core function:

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import { generateText } from 'ai';
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const result = await generateText({
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  model, // wrapped model with DevTools
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  prompt: 'What cities are in the United States?',
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});

Launch the viewer

Start the DevTools viewer:

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npx @ai-sdk/devtools

Open http://localhost:4983 to view your AI SDK interactions.

Captured data

The DevTools middleware captures the following information from your AI SDK calls:

• Input parameters and prompts: View the complete input sent to your LLM
• Output content and tool calls: Inspect generated text and tool invocations
• Token usage and timing: Monitor resource consumption and performance
• Raw provider data: Access complete request and response payloads

Runs and steps

DevTools organizes captured data into runs and steps:

• Run: A complete multi-step AI interaction, grouped by the initial prompt
• Step: A single LLM call within a run (e.g., one generateText or streamText call)

Multi-step interactions, such as those created by tool calling or agent loops, are grouped together as a single run with multiple steps.

How it works

The DevTools middleware intercepts all generateText and streamText calls through the language model middleware system. Captured data is stored locally in a JSON file (.devtools/generations.json) and served through a web UI built with Hono and React.

Security considerations

DevTools stores all AI interactions locally in plain text files, including:

• User prompts and messages
• LLM responses
• Tool call arguments and results
• API request and response data

Only use DevTools in local development environments. Do not enable DevTools in production or when handling sensitive data.