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How to connect Harness to Claude

Connect Claude Web, Desktop and Cowork to Harness MCP. Trigger deployment pipeline for your-service now, rollback last successful deployment in project, and more using natural language, with authentication handled for you.

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Harness is a Continuous Delivery platform exposing Core CD APIs to manage pipelines, executions, services, environments, and templates. Use it to automate and scale deployments with clear visibility and governance.

7 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 Harness account to Claude via Composio Connect, enabling it to trigger deployment pipeline for your-service now, rollback last successful deployment in project, list recent failed pipeline executions across environments, 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 Harness with

ChatGPTHermesAtomic Agent

Connecting Harness 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 Harness account

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

For example, ask Claude to:

  • "Trigger deployment pipeline for your-service now"
  • "Rollback last successful deployment in project"
  • "List recent failed pipeline executions across environments"

It will prompt you to authenticate and authorize access.

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

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

The Harness MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Harness account. It provides structured and secure access to your organizations, projects, pipelines, executions, services, environments, and templates, so your agent can find deployment resources, review pipeline activity, check execution status, inspect service environments, and discover reusable templates on your behalf.

  • Organization and project discovery: Have your agent list accessible organizations and projects, then narrow the results by organization, module, or search terms.
  • Pipeline exploration: Direct your agent to find pipelines in a project by name, search text, or Git branch.
  • Execution monitoring: Let the agent review pipeline executions and filter them by pipeline, status, search text, or ownership.
  • Service and environment visibility: Instruct your agent to find project services by deployment type, tags, storage, GitOps state, or search text, and list environments that match your criteria.
  • Template discovery: Have your agent search account templates by state, type, name, description, or other search text.

Troubleshooting

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

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

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

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

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

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

3. Why does the Harness authorization link not work?

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

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

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

The Harness connection can expire or lose permission.

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

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

Claude can manage the Harness connection for you.

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

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

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

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

Supported Tools

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

List Environments

List one page of environments in a Harness project, optionally filtered by identifiers or search text.

List Pipeline Executions

List one page of pipeline executions in a Harness project, optionally filtered by pipeline, status, search text, or current-user ownership.

List Organizations

List one page of Harness organizations accessible to the connected account, optionally filtered by identifier or search text.

List Pipelines

List one page of pipelines in a Harness project, optionally filtered by search text or Git branch.

List Projects

List one page of Harness projects accessible to the connected account, optionally within an organization or filtered by module and search text.

List Services

List one page of services in a Harness project, optionally filtered by identifiers, deployment type, tags, storage, GitOps state, or search text.

List Templates

List one page of account-scoped Harness templates, optionally filtered by template state, entity or child type, identifier, name, description, or search text.

FRAMEWORKS

How to build Harness MCP Agent with another framework

ChatGPT logo

ChatGPT

Use Harness MCP with ChatGPT

Hermes logo

Hermes

Use Harness MCP with Hermes

Atomic Agent logo

Atomic Agent

Use Harness MCP with Atomic Agent

FAQ

Frequently asked questions

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

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

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