How to integrate Ahrefs MCP with Pydantic AI

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Introduction

This guide walks you through connecting Ahrefs to Pydantic AI using the Composio tool router. By the end, you'll have a working Ahrefs agent that can get domain rating trend for competitor site, list all broken backlinks for my website, find keyword volume for 'ai tools' in us, show top referring domains for example.com through natural language commands.

This guide will help you understand how to give your Pydantic AI agent real control over a Ahrefs account through Composio's Ahrefs MCP server.

Before we dive in, let's take a quick look at the key ideas and tools involved.

TL;DR

Here's what you'll learn:
  • How to set up your Composio API key and User ID
  • How to create a Composio Tool Router session for Ahrefs
  • How to attach an MCP Server to a Pydantic AI agent
  • How to stream responses and maintain chat history
  • How to build a simple REPL-style chat interface to test your Ahrefs workflows

What is Pydantic AI?

Pydantic AI is a Python framework for building AI agents with strong typing and validation. It leverages Pydantic's data validation capabilities to create robust, type-safe AI applications.

Key features include:

  • Type Safety: Built on Pydantic for automatic data validation
  • MCP Support: Native support for Model Context Protocol servers
  • Streaming: Built-in support for streaming responses
  • Async First: Designed for async/await patterns

What is the Ahrefs MCP server, and what's possible with it?

The Ahrefs MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Ahrefs account. It provides structured and secure access to your SEO and marketing data, so your agent can perform actions like analyzing backlinks, researching keywords, auditing domain authority, and uncovering competitive insights on your behalf.

  • Comprehensive backlink analysis: Instantly retrieve detailed backlink profiles, stats, and broken link data for any website to inform your SEO strategy or spot link-building opportunities.
  • Keyword research and trends: Explore keyword overviews, search volumes by country, and discover matching or related terms to optimize content and target the right audience.
  • Domain authority tracking: Fetch up-to-date domain ratings or track historical changes to monitor the SEO health and growth of your own sites or competitors over time.
  • Batch competitor and site analysis: Analyze up to 100 domains or URLs at once to compare SEO metrics, spot weaknesses, and benchmark your performance against competitors efficiently.
  • Outbound link and partnership insights: Identify all external domains a site links to, helping you understand content strategy, partnerships, and potential link-building prospects.

Supported Tools & Triggers

Tools
Backlinks stats retrievalRetrieves comprehensive backlink statistics for a specified website or url using ahrefs' site explorer tool.
Batch Url AnalysisPerforms a batch analysis on multiple urls or domains using ahrefs' powerful seo metrics.
Domain rating for site explorerRetrieves the domain rating (dr) for a specified domain.
Domain rating historyRetrieves the historical domain rating (dr) data for a specified domain over time.
Explore keywords overviewRetrieves a comprehensive overview of keyword data from ahrefs' keywords explorer tool.
Explore keyword volume by countryRetrieves the search volume data for specified keywords across different countries using ahrefs' keywords explorer tool.
Explore linked domains of a siteRetrieves a list of external domains that the specified target website or url links to, using ahrefs' site explorer functionality.
Explore matching terms for keywordsThe keywords explorer matching terms endpoint retrieves a list of keyword phrases that match or contain the specified keyword from ahrefs' vast database.
Fetch all backlinksRetrieves a comprehensive list of backlinks for a specified website or url using ahrefs' site explorer tool.
Fetch broken backlinks dataRetrieves a list of broken backlinks for a specified website using ahrefs' site explorer tool.
Fetch competitors overviewRetrieves a comprehensive overview of competitor data in relation to keyword rankings and organic search performance.
Fetch rank tracker overviewThe getranktrackeroverview endpoint retrieves a comprehensive summary of keyword rankings and seo performance data from ahrefs' rank tracker tool.
Fetch site explorer referring domainsRetrieves a list of domains that have backlinks pointing to a specified target website.
Fetch total search volume historyRetrieves the historical total search volume data for specified keywords using ahrefs' site explorer tool.
Get serp overviewRetrieves a comprehensive overview of search engine results pages (serp) data for specified keywords or queries.
Get site audit projectsRetrieves a list of site audit projects associated with the authenticated ahrefs account.
Get site explorer country metricsRetrieves country-specific site explorer metrics for a given website from ahrefs.
Get site explorer linked anchors externalThe site-explorer-linked-anchors-external endpoint retrieves data about external anchor texts linking to a specified target website.
Get url rating historyRetrieves the historical url rating data for a specified url over time.
Linked anchors explorerRetrieves information about internal linked anchors for a specified website using the ahrefs api.
List best by external linksThe 'get best by external links' endpoint retrieves a list of pages from a specified website, ranked by the number of external links pointing to them.
Pages by traffic overviewRetrieves a list of pages from a specified website, ordered by their estimated organic search traffic.
Retrieve anchor dataRetrieves anchor text data for a specified website or url using ahrefs' site explorer tool.
Retrieve best by internal linksRetrieves data on the best-performing internal links within a specified website using ahrefs' site explorer feature.
Retrieve crawler ip rangesRetrieves the list of ip address ranges used by ahrefs' web crawler (ahrefsbot).
Retrieve organic competitorsThe getorganiccompetitors endpoint in the ahrefs api provides a comprehensive analysis of websites competing for organic search rankings with a specified target domain.
Retrieve organic keywordsRetrieves organic keywords data for a specified website using ahrefs' site explorer tool.
Retrieve outlinks statsRetrieves comprehensive statistics about outgoing links (outlinks) from a specified website using ahrefs' site explorer tool.
Retrieve paid pages dataRetrieves information about paid pages (ppc advertising) for a specified website using ahrefs' site explorer tool.
Retrieve public crawler ipsRetrieves a list of ip addresses currently used by ahrefsbot, ahrefs' web crawler.
Retrieve related termsThe keywords explorer related terms endpoint retrieves a list of related terms for a given keyword using ahrefs' extensive keyword database.
Retrieve site explorer keywords historyRetrieves historical keyword performance data for a specified website or domain using ahrefs' site explorer.
Retrieve site explorer metricsThe getsiteexplorermetrics endpoint retrieves comprehensive seo metrics for a specified website using ahrefs' site explorer tool.
Retrieve site explorer metrics historyRetrieves historical seo metrics data for a specified website over a given time period.
Retrieve site explorer pages historyThe get site explorer pages history endpoint retrieves historical data about specific pages or domains from ahrefs' site explorer.
Retrieve site explorer referring domains historyRetrieves the historical data of referring domains for a specified website or url over time.
Retrieve subscription limits and usageRetrieves detailed information about the current subscription limits and usage for an ahrefs account.
Retrieve top pages from site explorerRetrieves data about the top-performing pages of a specified website using ahrefs' site explorer tool.
Retrieve volume historyRetrieves the historical search volume data for a specified keyword using ahrefs' keywords explorer tool.
Search suggestions explorerRetrieves search suggestions for a given keyword or phrase using ahrefs' keywords explorer tool.

What is the Composio tool router, and how does it fit here?

What is Tool Router?

Composio's Tool Router helps agents find the right tools for a task at runtime. You can plug in multiple toolkits (like Gmail, HubSpot, and GitHub), and the agent will identify the relevant app and action to complete multi-step workflows. This can reduce token usage and improve the reliability of tool calls. Read more here: Getting started with Tool Router

The tool router generates a secure MCP URL that your agents can access to perform actions.

How the Tool Router works

The Tool Router follows a three-phase workflow:

  1. Discovery: Searches for tools matching your task and returns relevant toolkits with their details.
  2. Authentication: Checks for active connections. If missing, creates an auth config and returns a connection URL via Auth Link.
  3. Execution: Executes the action using the authenticated connection.

Step-by-step Guide

Prerequisites

Before starting, make sure you have:
  • Python 3.9 or higher
  • A Composio account with an active API key
  • Basic familiarity with Python and async programming

Getting API Keys for OpenAI and Composio

OpenAI API Key
  • Go to the OpenAI dashboard and create an API key. You'll need credits to use the models, or you can connect to another model provider.
  • Keep the API key safe.
Composio API Key
  • Log in to the Composio dashboard.
  • Navigate to your API settings and generate a new API key.
  • Store this key securely as you'll need it for authentication.

Install dependencies

bash
pip install composio pydantic-ai python-dotenv

Install the required libraries.

What's happening:

  • composio connects your agent to external SaaS tools like Ahrefs
  • pydantic-ai lets you create structured AI agents with tool support
  • python-dotenv loads your environment variables securely from a .env file

Set up environment variables

bash
COMPOSIO_API_KEY=your_composio_api_key_here
USER_ID=your_user_id_here
OPENAI_API_KEY=your_openai_api_key

Create a .env file in your project root.

What's happening:

  • COMPOSIO_API_KEY authenticates your agent to Composio's API
  • USER_ID associates your session with your account for secure tool access
  • OPENAI_API_KEY to access OpenAI LLMs

Import dependencies

python
import asyncio
import os
from dotenv import load_dotenv
from composio import Composio
from pydantic_ai import Agent
from pydantic_ai.mcp import MCPServerStreamableHTTP

load_dotenv()
What's happening:
  • We load environment variables and import required modules
  • Composio manages connections to Ahrefs
  • MCPServerStreamableHTTP connects to the Ahrefs MCP server endpoint
  • Agent from Pydantic AI lets you define and run the AI assistant

Create a Tool Router Session

python
async def main():
    api_key = os.getenv("COMPOSIO_API_KEY")
    user_id = os.getenv("USER_ID")
    if not api_key or not user_id:
        raise RuntimeError("Set COMPOSIO_API_KEY and USER_ID in your environment")

    # Create a Composio Tool Router session for Ahrefs
    composio = Composio(api_key=api_key)
    session = composio.create(
        user_id=user_id,
        toolkits=["ahrefs"],
    )
    url = session.mcp.url
    if not url:
        raise ValueError("Composio session did not return an MCP URL")
What's happening:
  • We're creating a Tool Router session that gives your agent access to Ahrefs tools
  • The create method takes the user ID and specifies which toolkits should be available
  • The returned session.mcp.url is the MCP server URL that your agent will use

Initialize the Pydantic AI Agent

python
# Attach the MCP server to a Pydantic AI Agent
ahrefs_mcp = MCPServerStreamableHTTP(url, headers={"x-api-key": COMPOSIO_API_KEY})
agent = Agent(
    "openai:gpt-5",
    toolsets=[ahrefs_mcp],
    instructions=(
        "You are a Ahrefs assistant. Use Ahrefs tools to help users "
        "with their requests. Ask clarifying questions when needed."
    ),
)
What's happening:
  • The MCP client connects to the Ahrefs endpoint
  • The agent uses GPT-5 to interpret user commands and perform Ahrefs operations
  • The instructions field defines the agent's role and behavior

Build the chat interface

python
# Simple REPL with message history
history = []
print("Chat started! Type 'exit' or 'quit' to end.\n")
print("Try asking the agent to help you with Ahrefs.\n")

while True:
    user_input = input("You: ").strip()
    if user_input.lower() in {"exit", "quit", "bye"}:
        print("\nGoodbye!")
        break
    if not user_input:
        continue

    print("\nAgent is thinking...\n", flush=True)

    async with agent.run_stream(user_input, message_history=history) as stream_result:
        collected_text = ""
        async for chunk in stream_result.stream_output():
            text_piece = None
            if isinstance(chunk, str):
                text_piece = chunk
            elif hasattr(chunk, "delta") and isinstance(chunk.delta, str):
                text_piece = chunk.delta
            elif hasattr(chunk, "text"):
                text_piece = chunk.text
            if text_piece:
                collected_text += text_piece
        result = stream_result

    print(f"Agent: {collected_text}\n")
    history = result.all_messages()
What's happening:
  • The agent reads input from the terminal and streams its response
  • Ahrefs API calls happen automatically under the hood
  • The model keeps conversation history to maintain context across turns

Run the application

python
if __name__ == "__main__":
    asyncio.run(main())
What's happening:
  • The asyncio loop launches the agent and keeps it running until you exit

Complete Code

Here's the complete code to get you started with Ahrefs and Pydantic AI:

python
import asyncio
import os
from dotenv import load_dotenv
from composio import Composio
from pydantic_ai import Agent
from pydantic_ai.mcp import MCPServerStreamableHTTP

load_dotenv()

async def main():
    api_key = os.getenv("COMPOSIO_API_KEY")
    user_id = os.getenv("USER_ID")
    if not api_key or not user_id:
        raise RuntimeError("Set COMPOSIO_API_KEY and USER_ID in your environment")

    # Create a Composio Tool Router session for Ahrefs
    composio = Composio(api_key=api_key)
    session = composio.create(
        user_id=user_id,
        toolkits=["ahrefs"],
    )
    url = session.mcp.url
    if not url:
        raise ValueError("Composio session did not return an MCP URL")

    # Attach the MCP server to a Pydantic AI Agent
    ahrefs_mcp = MCPServerStreamableHTTP(url, headers={"x-api-key": COMPOSIO_API_KEY})
    agent = Agent(
        "openai:gpt-5",
        toolsets=[ahrefs_mcp],
        instructions=(
            "You are a Ahrefs assistant. Use Ahrefs tools to help users "
            "with their requests. Ask clarifying questions when needed."
        ),
    )

    # Simple REPL with message history
    history = []
    print("Chat started! Type 'exit' or 'quit' to end.\n")
    print("Try asking the agent to help you with Ahrefs.\n")

    while True:
        user_input = input("You: ").strip()
        if user_input.lower() in {"exit", "quit", "bye"}:
            print("\nGoodbye!")
            break
        if not user_input:
            continue

        print("\nAgent is thinking...\n", flush=True)

        async with agent.run_stream(user_input, message_history=history) as stream_result:
            collected_text = ""
            async for chunk in stream_result.stream_output():
                text_piece = None
                if isinstance(chunk, str):
                    text_piece = chunk
                elif hasattr(chunk, "delta") and isinstance(chunk.delta, str):
                    text_piece = chunk.delta
                elif hasattr(chunk, "text"):
                    text_piece = chunk.text
                if text_piece:
                    collected_text += text_piece
            result = stream_result

        print(f"Agent: {collected_text}\n")
        history = result.all_messages()

if __name__ == "__main__":
    asyncio.run(main())

Conclusion

You've built a Pydantic AI agent that can interact with Ahrefs through Composio's Tool Router. With this setup, your agent can perform real Ahrefs actions through natural language. You can extend this further by:
  • Adding other toolkits like Gmail, HubSpot, or Salesforce
  • Building a web-based chat interface around this agent
  • Using multiple MCP endpoints to enable cross-app workflows (for example, Gmail + Ahrefs for workflow automation)
This architecture makes your AI agent "agent-native", able to securely use APIs in a unified, composable way without custom integrations.

How to build Ahrefs MCP Agent with another framework

OpenAI Agents SDK

OpenAI Agents SDK

Use Ahrefs MCP with OpenAI Agents SDK

Claude Agent SDK

Claude Agent SDK

Use Ahrefs MCP with Claude Agent SDK

Google ADK

Google ADK

Use Ahrefs MCP with Google ADK

LangChain

LangChain

Use Ahrefs MCP with LangChain

Vercel AI SDK

Vercel AI SDK

Use Ahrefs MCP with Vercel AI SDK

Mastra AI

Mastra AI

Use Ahrefs MCP with Mastra AI

LlamaIndex

LlamaIndex

Use Ahrefs MCP with LlamaIndex

CrewAI

CrewAI

Use Ahrefs MCP with CrewAI

Claude Code

Claude Code

Use Ahrefs MCP with Claude Code

FAQ

What are the differences in Tool Router MCP and Ahrefs MCP?

With a standalone Ahrefs MCP server, the agents and LLMs can only access a fixed set of Ahrefs tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Ahrefs and many other apps based on the task at hand, all through a single MCP endpoint.

Can I use Tool Router MCP with Pydantic AI?

Yes, you can. Pydantic AI fully supports MCP integration. You get structured tool calling, message history handling, and model orchestration while Tool Router takes care of discovering and serving the right Ahrefs tools.

Can I manage the permissions and scopes for Ahrefs while using Tool Router?

Yes, absolutely. You can configure which Ahrefs scopes and actions are allowed when connecting your account to Composio. You can also bring your own OAuth credentials or API configuration so you keep full control over what the agent can do.

How safe is my data with Composio Tool Router?

All sensitive data such as tokens, keys, and configuration is fully encrypted at rest and in transit. Composio is SOC 2 Type 2 compliant and follows strict security practices so your Ahrefs data and credentials are handled as safely as possible.

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