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How to connect Trestle to Claude

Connect Claude Web, Desktop and Cowork to Trestle MCP. Validate this phone number before contacting, identify the caller behind this number, and more using natural language, with authentication handled for you.

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Trestle is an identity data API platform for phone, caller, and address data. It helps businesses verify contact details and improve data quality.

3 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 Trestle account to Claude via Composio Connect, enabling it to validate this phone number before contacting, identify the caller behind this number, correct and validate this business address, 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.

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Connecting Trestle 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 Trestle account

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

For example, ask Claude to:

  • "Validate this phone number before contacting"
  • "Identify the caller behind this number"
  • "Correct and validate this business address"

It will prompt you to authenticate and authorize access.

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

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

The Trestle MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Trestle account. It provides structured and secure access to identity data, so your agent can validate phone numbers, identify likely phone owners, verify contact details, and review phone, email, address, and IP match signals on your behalf.

  • Phone number validation: Have your agent check phone activity, carrier, line type, country, and prepaid status for supplied numbers.
  • Phone owner lookup: Let the agent find ranked person or business owners and current addresses associated with a phone number.
  • Contact verification: Direct your agent to verify supplied contact details using phone, email, address, and IP match signals.
  • Inbound lead checks: Instruct your agent to assess contact information for identity or inbound-lead verification before your team follows up.

Troubleshooting

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

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

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

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

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

  • 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 Trestle.
  • If it fails again, send the error and the ofid_ reference id to support@composio.dev.

3. Why does the Trestle authorization link not work?

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

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

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

The Trestle connection can expire or lose permission.

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

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

Claude can manage the Trestle connection for you.

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

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

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

  • In Claude Desktop, open Customize > Connectors.
  • Next to Composio, click ⋮ and click Clear cache.
  • If Trestle 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 Trestle.
TOOLS

Supported Tools

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

Look Up Phone Owners

Look up ranked person or business owners and current addresses associated with a supplied phone number for permitted caller-identification or identity-management use.

Validate Phone

Validate a supplied phone number and return activity, carrier, line-type, country, and prepaid signals.

Verify Contact

Verify supplied contact details for identity or inbound-lead verification and return phone, email, address, and IP match signals.

FRAMEWORKS

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ChatGPT logo

ChatGPT

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Hermes logo

Hermes

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Atomic Agent logo

Atomic Agent

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FAQ

Frequently asked questions

With a standalone Trestle MCP server, the agents and LLMs can only access a fixed set of Trestle tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Trestle 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 Trestle tools.

Yes, absolutely. You can configure which Trestle 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 Trestle data and credentials are handled as safely as possible.

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