Tabstack for the Claude Agent SDK

@tabstack/claude-agent gives your Claude Agent SDK agents reliable web access: schema-enforced extraction, multi-source research, AI transformation, and browser automation, exposed as an in-process MCP server and backed by the official @tabstack/sdk.

Unlike the other integrations, which hand you tool objects, this one hands you a ready-built MCP server to drop into a query() call.

Install

npm

npm install @tabstack/claude-agent @anthropic-ai/claude-agent-sdk zod

pnpm

pnpm add @tabstack/claude-agent @anthropic-ai/claude-agent-sdk zod

yarn

yarn add @tabstack/claude-agent @anthropic-ai/claude-agent-sdk zod

@anthropic-ai/claude-agent-sdk (v0.3 or later) and zod are peer dependencies.

Zod 4 is required, because the Claude Agent SDK depends on it.

The agent loop runs on Claude, so ANTHROPIC_API_KEY must be set alongside your Tabstack key.

Create and Setup Your API Key

Before you can start using Tabstack API, you’ll need to create an API key and set it up in your environment.

1. Create Your API Key

1. Visit the Tabstack Console
2. Sign in to your account (or create one if you haven’t already)
3. Navigate to the API Keys section and click the “Manage API Keys”
4. Once you are on the API Keys page, Click “Create New API Key”
5. Give your key a descriptive name (e.g., “Development”, “Production”) and click the “Create API Key”
6. Copy the generated API key and store it securely

Your API key will only be shown once. Make sure to copy and store it in a secure location.

2. Set Up Environment Variable

For security and convenience, we recommend storing your API key as an environment variable rather than hardcoding it in your scripts.

macOS/Linux

# Add to your shell profile (~/.bashrc, ~/.zshrc, or ~/.bash_profile)
export TABSTACK_API_KEY="your_api_key_here"

# Or set it temporarily for the current session
export TABSTACK_API_KEY="your_api_key_here"

# Reload your shell or run:
source ~/.bashrc  # or ~/.zshrc

Windows (Command Prompt)

# Set temporarily for current session
set TABSTACK_API_KEY=your_api_key_here

# Set permanently (requires restart)
setx TABSTACK_API_KEY "your_api_key_here"

Windows (PowerShell)

# Set temporarily for current session
$env:TABSTACK_API_KEY = "your_api_key_here"

# Set permanently for current user
[Environment]::SetEnvironmentVariable("TABSTACK_API_KEY", "your_api_key_here", "User")

3. Verify Your Setup

Test that your environment variable is set correctly:

macOS/Linux/Windows (Git Bash):

echo $TABSTACK_API_KEY

Windows (Command Prompt):

echo %TABSTACK_API_KEY%

Windows (PowerShell):

echo $env:TABSTACK_API_KEY

You should see your API key printed in the terminal.

Quickstart

tabstackServer is a ready-built in-process MCP server, and tabstackAllowedTools pre-approves every Tabstack tool. Wire both into a query() call:

import { query } from "@anthropic-ai/claude-agent-sdk";
import {
  tabstackAllowedTools,
  tabstackMcpServerName,
  tabstackServer,
} from "@tabstack/claude-agent";

for await (const message of query({
  prompt: "What are Vercel's current pricing plans, with sources?",
  options: {
    mcpServers: { [tabstackMcpServerName]: tabstackServer },
    allowedTools: tabstackAllowedTools,
  },
})) {
  if (message.type === "result" && message.subtype === "success") {
    console.log(message.result);
  }
}

The server resolves TABSTACK_API_KEY lazily on first tool call, so importing the package never requires a key.

To stop the SDK’s built-in tools (WebFetch, Bash, and friends) from shadowing the Tabstack ones, pass tools: [] in options so the agent only has the MCP tools you registered.

The tools

Tool	What it does
extract_structured_data	Pull specific fields from a URL into a JSON shape you define.
extract_page_content	Fetch a page as clean markdown.
research_question	Synthesize a cited answer across multiple pages.
generate_structured_data	Fetch a page, then AI-transform it into derived or reshaped JSON.
automate_browser_task	Run a multi-step, natural-language browser task.

Claude sees each one under its fully qualified MCP name, mcp__tabstack__<tool_name>. That is what tabstackAllowedTools contains, so it is equivalent to allowing mcp__tabstack__*.

Tool inputs

The model fills these in, but it helps to know the shapes:

• extract_structured_data: url, json_schema_json (a JSON-encoded JSON Schema string).
• extract_page_content: url.
• research_question: query.
• generate_structured_data: url, instructions, json_schema_json.
• automate_browser_task: task, plus optional url, guardrails, data, country, max_iterations, max_validation_attempts.

Each tool’s schema is registered with the SDK, so Claude’s arguments are validated before the tool body runs. See Schema design for writing json_schema_json that extracts reliably.

Optional inputs

The model can pass these for finer control; they are sent to Tabstack only when present.

• extract_structured_data, extract_page_content, generate_structured_data:
  • effort: "min", "standard", or "max". Use "max" for JS-heavy pages. See Effort levels.
  • nocache: bypass the cache.
  • country: ISO 3166-1 alpha-2 code for geotargeting.
• research_question: mode ("fast" or "balanced"), nocache.
• automate_browser_task: guardrails (constraints on what the agent may do), data (context for form filling), country, max_iterations, max_validation_attempts.

Configuration

For a custom API key or base URL, or to reuse one client, build the server explicitly:

import { query } from "@anthropic-ai/claude-agent-sdk";
import {
  createTabstackClaudeAgentServer,
  tabstackAllowedTools,
  tabstackMcpServerName,
} from "@tabstack/claude-agent";

const server = createTabstackClaudeAgentServer({ apiKey: process.env.MY_KEY });
// or pass an SDK client you already have: createTabstackClaudeAgentServer({ client })

await query({
  prompt: "...",
  options: {
    mcpServers: { [tabstackMcpServerName]: server },
    allowedTools: tabstackAllowedTools,
  },
});

To assemble the server yourself, createTabstackClaudeAgentTools(config) returns the raw tool array for your own createSdkMcpServer({ name, version, tools }) call.

Error handling

When a tool call fails, the handler normalizes the failure to a TabstackToolError (a clean message plus an HTTP status for API errors) and returns it as an MCP error result (isError: true). Claude reads a useful message and can retry or explain, rather than seeing a raw exception.

Related

• Integrations overview
• Tabstack MCP server
• Tabstack TypeScript SDK
• OpenAI Agents SDK integration and Vercel AI SDK integration