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How to connect Blocknative to Claude

Connect Claude Web, Desktop and Cowork to Blocknative MCP. Monitor transaction status for a given hash, fetch current ethereum gas price distribution, and more using natural language, with authentication handled for you.

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Blocknative delivers real-time mempool monitoring and transaction management for public blockchains. Instantly track pending transactions and optimize blockchain interactions with live data.

10 Tools

Introduction

Claude is Anthropic's AI assistant, available on the web, in the desktop app, and on mobile. Cowork is its agent for knowledge work, and it runs on all of those surfaces too. Connected to your apps, Claude can work with your files and services to accomplish complex tasks on your behalf.

This guide walks you through the easiest and most secure way to connect your Blocknative account to Claude via Composio Connect, enabling it to monitor transaction status for a given hash, fetch current Ethereum gas price distribution, list all supported blockchains for monitoring, and more such actions on your behalf without compromising your account security.

Setup is the same on Claude Web, Desktop, and Cowork, and you only need to do it once. The connector is tied to your account, so it's available in all three.

Also integrate Blocknative with

Claude CodeOpenAI Agents SDKClaude Agent SDKCodexOpenClawHermesAtomic AgentGoogle ADKLangChainVercel AI SDKMastra AILlamaIndexCrewAIPydantic AIAutoGen

Connecting Blocknative to Claude Web, Desktop, and Cowork

Two ways to add the Composio connector. Pick whichever you prefer.

1. Add with one click

Click the button. Claude opens with the Composio connector filled in. Click Add, then go to step 2.

Add to Claude

Add manually

In Claude Desktop, click Customize in the left sidebar, then select Connectors and click the + icon at the top.

Claude Desktop connectors screen with Add custom connector selected

Click Add custom connector and paste in the Composio MCP server URL:

bash
https://connect.composio.dev/mcp
Add custom connector dialog with Composio MCP server URL

2. Authorize in your browser

Click Connect. You'll be redirected to a browser window where you can authorize Composio to continue.

Composio authorization screen for Claude Web, Desktop, and Cowork

3. Connect your Blocknative account

Back in Claude, ask it to connect to Blocknative or give it any Blocknative-related task.

For example, ask Claude to:

  • "Monitor transaction status for a given hash"
  • "Fetch current Ethereum gas price distribution"
  • "List all supported blockchains for monitoring"

It will prompt you to authenticate and authorize access.

That's it. Composio's tools are now available in Claude, and your Blocknative account is ready to use.

What is the Blocknative Claude Connector, and what's possible with it?

The Blocknative MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Blocknative account. It provides structured and secure access to real-time mempool data and transaction management features across public blockchains, so your agent can monitor transactions, analyze gas prices, configure filters, and manage blockchain event subscriptions on your behalf.

  • Real-time mempool monitoring: Instruct your agent to subscribe to Ethereum transaction hashes or addresses and receive instant updates on their status and events.
  • Gas price analysis and estimation: Have your agent fetch current gas price distributions, base fee predictions, and inclusion probability estimates to help optimize transaction fees.
  • Customizable event filters: Let your agent configure advanced mempool filters and ABI decoding, so you can track only the events or transactions that matter to your workflow.
  • Multichain event subscriptions: Enable your agent to subscribe or unsubscribe to transaction and account events across multiple supported blockchains using the Blocknative multichain SDK.
  • Supported chain discovery: Ask your agent to list and discover which blockchains and gas oracles are available for monitoring and analytics.

Troubleshooting

1. Why does Claude not use the Composio connector for Blocknative?

The connector can show as connected, but Claude must use it in each Blocknative conversation.

  • Click + at the lower left of the chat, or type /.
  • Hover Connectors.
  • Turn on Composio.
  • Ask Claude to connect to Blocknative again.

2. Why does Claude show an MCP server error before Blocknative connects?

Claude can show Couldn't reach the MCP server or Authorization with the MCP server failed when you add the connector for Blocknative.

  • Check that the connector URL is https://connect.composio.dev/mcp.
  • Connectors run from Anthropic's cloud, so your device network is usually not the problem.
  • Add the connector again from Customize > Connectors, then ask Claude to connect Blocknative.
  • If it fails again, send the error and the ofid_ reference id to support@composio.dev.

3. Why does the Blocknative authorization link not work?

The Composio connector is one server. Your Blocknative account connects separately when Claude asks for it.

  • If the browser does not open, or the link expires, ask Claude to retry the Blocknative connection.
  • Composio creates a fresh Blocknative authorization link.
  • Open that link in your browser and finish the Blocknative sign-in.

4. Why do Blocknative actions fail after they worked before?

The Blocknative connection can expire or lose permission.

  • Ask Claude to inspect the Blocknative connection.
  • If the connection is unhealthy, disconnect it when Claude prompts you.
  • Reconnect the Blocknative account and retry the action.
  • If Claude shows a permission prompt, approve it before Claude changes data in Blocknative.
  • If the action still fails with a permission error, check that the connected account has that permission in Blocknative itself.

5. How do I switch to a different Blocknative account?

Claude can manage the Blocknative connection for you.

  • Ask Claude to disconnect or delete the current Blocknative account.
  • Ask Claude to connect Blocknative again.
  • Open the new Composio authorization link for Blocknative.
  • Sign in with the other Blocknative account in the browser.
  • After the account connects, ask Claude to retry the Blocknative task.

6. Why is my Blocknative connection missing in Claude Desktop or on a Team plan?

The connector belongs to your Claude account, so your Blocknative connection works in Claude Web, Desktop, and Cowork.

  • In Claude Desktop, open Customize > Connectors.
  • Next to Composio, click ⋮ and click Clear cache.
  • If Blocknative tools still do not appear, click ⋮, disconnect, remove the connector, and add it again.
  • On Team or Enterprise, an Owner or Primary Owner must enable the connector before you can connect Blocknative.
TOOLS

Supported Tools

Every Blocknative action and event your agent gets out of the box.

Configure Mempool Filters

Tool to configure filters and ABI decoding for Ethereum mempool transactions.

Get Gas Price Distribution

Tool to retrieve the current mempool gas price distribution breakdown.

Get Gas Oracles

Tool to retrieve metadata on supported gas oracles per chain.

Get Gas Prices

Tool to fetch gas price estimates for specific inclusion probabilities.

Get Supported Chains

Tool to retrieve supported chains metadata.

Get Base Fee Estimates

Get real-time gas fee predictions for Ethereum mainnet's next 5 blocks.

Subscribe Multichain

Generate WebSocket connection details to subscribe to real-time blockchain events (transactions or account activity) across multiple chains via Blocknative's Multichain API.

Subscribe Transaction Hash

Tool to subscribe to transaction state change events of an Ethereum transaction hash.

Unsubscribe Multichain

Tool to unsubscribe from events across multiple chains using the Multichain SDK.

Unsubscribe Transaction Hash

Tool to unsubscribe from transaction state change events for an Ethereum transaction hash.

FRAMEWORKS

How to build Blocknative MCP Agent with another framework

Claude Code logo

Claude Code

Use Blocknative MCP with Claude Code

OpenAI Agents SDK logo

OpenAI Agents SDK

Use Blocknative MCP with OpenAI Agents SDK

Claude Agent SDK logo

Claude Agent SDK

Use Blocknative MCP with Claude Agent SDK

Codex logo

Codex

Use Blocknative MCP with Codex

OpenClaw logo

OpenClaw

Use Blocknative MCP with OpenClaw

Hermes logo

Hermes

Use Blocknative MCP with Hermes

Atomic Agent logo

Atomic Agent

Use Blocknative MCP with Atomic Agent

Google ADK logo

Google ADK

Use Blocknative MCP with Google ADK

LangChain logo

LangChain

Use Blocknative MCP with LangChain

Vercel AI SDK logo

Vercel AI SDK

Use Blocknative MCP with Vercel AI SDK

Mastra AI logo

Mastra AI

Use Blocknative MCP with Mastra AI

LlamaIndex logo

LlamaIndex

Use Blocknative MCP with LlamaIndex

CrewAI logo

CrewAI

Use Blocknative MCP with CrewAI

Pydantic AI logo

Pydantic AI

Use Blocknative MCP with Pydantic AI

AutoGen logo

AutoGen

Use Blocknative MCP with AutoGen

FAQ

Frequently asked questions

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

Yes, you can. Claude Cowork 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 Blocknative tools.

Yes, absolutely. You can configure which Blocknative 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.

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 Blocknative data and credentials are handled as safely as possible.

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