# How to connect Harness to Claude ```json { "title": "How to connect Harness to Claude", "toolkit": "Harness", "toolkit_slug": "harness", "framework": "Claude Cowork", "framework_slug": "claude-cowork", "url": "https://composio.dev/toolkits/harness/framework/claude-cowork", "markdown_url": "https://composio.dev/toolkits/harness/framework/claude-cowork.md", "updated_at": "2026-10-12T12:48:31.569Z" } ``` ## 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 - [ChatGPT](https://composio.dev/toolkits/harness/framework/chatgpt) - [Hermes](https://composio.dev/toolkits/harness/framework/hermes-agent) - [Atomic Agent](https://composio.dev/toolkits/harness/framework/atomic-agent) ## Connect Harness to Claude Cowork ### 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](https://claude.ai/customize/connectors?modal=add-custom-connector&connectorName=Composio&connectorUrl=https%3A%2F%2Fconnect.composio.dev%2Fmcp) ### Add manually In Claude Desktop, click Customize in the left sidebar, then select Connectors and click the + icon at the top. Click Add custom connector and paste in the Composio MCP server URL: ```bash https://connect.composio.dev/mcp ``` ## What is the Harness MCP server, 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. ## Supported Tools | Tool slug | Name | Description | |---|---|---| | `HARNESS_LIST_ENVIRONMENTS` | List Environments | List one page of environments in a Harness project, optionally filtered by identifiers or search text. | | `HARNESS_LIST_EXECUTIONS` | List Pipeline Executions | List one page of pipeline executions in a Harness project, optionally filtered by pipeline, status, search text, or current-user ownership. | | `HARNESS_LIST_ORGANIZATIONS` | List Organizations | List one page of Harness organizations accessible to the connected account, optionally filtered by identifier or search text. | | `HARNESS_LIST_PIPELINES` | List Pipelines | List one page of pipelines in a Harness project, optionally filtered by search text or Git branch. | | `HARNESS_LIST_PROJECTS` | List Projects | List one page of Harness projects accessible to the connected account, optionally within an organization or filtered by module and search text. | | `HARNESS_LIST_SERVICES` | List Services | List one page of services in a Harness project, optionally filtered by identifiers, deployment type, tags, storage, GitOps state, or search text. | | `HARNESS_LIST_TEMPLATES` | 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. | ## Supported Triggers None listed. ## 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. ## Creating MCP Server - Stand-alone vs Composio SDK The Harness MCP server connects Claude Web, Desktop, and Cowork to your Harness account through Composio. Once connected, Claude can use the available Harness tools and triggers to complete tasks on your behalf. ## Complete Code None listed. ## How to build Harness MCP Agent with another framework - [ChatGPT](https://composio.dev/toolkits/harness/framework/chatgpt) - [Hermes](https://composio.dev/toolkits/harness/framework/hermes-agent) - [Atomic Agent](https://composio.dev/toolkits/harness/framework/atomic-agent) ## Related Toolkits - [Supabase](https://composio.dev/toolkits/supabase) - Supabase is an open-source backend platform offering scalable Postgres databases, authentication, storage, and real-time APIs. It lets developers build modern apps without managing infrastructure. - [Codeinterpreter](https://composio.dev/toolkits/codeinterpreter) - Codeinterpreter is a Python-based coding environment with built-in data analysis and visualization. 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It makes it easy for teams to organize data and automate workflows without writing code. ## Frequently Asked Questions ### What are the differences in Tool Router MCP and Harness MCP? 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. ### Can I use Tool Router MCP with Claude Cowork? 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. ### Can I manage the permissions and scopes for Harness while using Tool Router? 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. ### 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 Harness data and credentials are handled as safely as possible. --- [See all toolkits](https://composio.dev/toolkits) · [Composio docs](https://docs.composio.dev/llms.txt)