What is Harmonic MCP?

Model Context Protocol (MCP) is a protocol that lets AI assistants like Claude and ChatGPT connect to external tools and data sources - so instead of just answering questions from memory, they can take actions and retrieve live data on your behalf.

Harmonic MCP connects your AI client directly to Harmonic's data platform, giving you access to Harmonic's company, people, and investor data from any AI assistant, automation pipeline, or MCP-compatible client.

Quick setup

Connecting via Claude

The fastest way to get started is through Claude's built-in Connectors directory, available on both Claude Web and Claude Desktop:

Go to claude.ai or open Claude Desktop
Click your profile icon → Settings
Select Connectors from the left menu
Under the Web tab, find Harmonic ("Discover, research, and enrich companies and people")
Click the + button to add it
Complete the OAuth flow by logging into your Harmonic account

Once connected, you can immediately start asking Claude questions about companies, people, and investors using Harmonic's data.

Connecting via Claude Code

To add the Harmonic MCP server to Claude Code, run the following command:

bash

claude mcp add --transport http harmonic https://mcp.api.harmonic.ai/

After adding the server, authenticate by running:

bash

claude /mcp

Follow the OAuth flow to log into your Harmonic account. Once authenticated, you can start using Harmonic tools directly in Claude Code.

Connecting via ChatGPT

You can enable MCP servers on ChatGPT with a Pro, Plus, Business, Enterprise, or Education account. Follow the OpenAI documentation for setup instructions. Use the following parameters:

Server URL: https://mcp.api.harmonic.ai
Connection mechanism: OAuth

Connecting via other MCP clients

For any MCP client that supports manual server configuration (Claude Desktop, Cursor, Windsurf, etc.), you'll need:

Server URL: https://mcp.api.harmonic.ai (HTTP, recommended) or https://mcp.api.harmonic.ai/sse (SSE)
Authentication: OAuth 2.0 (automatically discovered)

Most clients use a JSON configuration file. Here's an example using HTTP transport (recommended):

{
  "mcpServers": {
    "harmonic": {
      "transport": {
        "type": "http",
        "url": "https://mcp.api.harmonic.ai"
      }
    }
  }
}

Or using SSE transport:

{
  "mcpServers": {
    "harmonic": {
      "transport": {
        "type": "sse",
        "url": "https://mcp.api.harmonic.ai/sse"
      }
    }
  }
}

After updating the configuration, restart your MCP client. It will automatically detect the OAuth endpoints and prompt you to log in via console.harmonic.ai.

Prerequisites

A Harmonic account (sign up at console.harmonic.ai)
An MCP-compatible client (AI chatbots like Claude Desktop/Web, ChatGPT, automation tools, or custom applications)

Authentication options

You can authenticate with the Harmonic MCP server using either method:

OAuth 2.0 – Recommended for interactive applications. The OAuth flow will redirect you to console.harmonic.ai to log in.
API Key – Recommended for programmatic workflows and server-to-server integrations. Get your API key from the API Usage Dashboard.

MCP access & limits

How MCP usage is metered depends on how you authenticate.

Authenticating with an API key

Requests consume API credits from your team's pool, with the same access and limitations as direct API usage. No additional configuration is needed.

Authenticating as a user (OAuth)

When you sign in through an MCP client like Claude, ChatGPT, or Cursor using your Harmonic account, your access depends on your team's API plan:

No API access: Each user gets 10 requests per day at no cost. Deal data is not available.
Limited API access: Each user gets 10 requests per day at no cost. To allow MCP requests to draw from your team's API credit pool (with no daily cap), a team admin must enable "Use API credits for MCP requests" in the MCP integration settings here.
Unlimited API access: There is no limit on MCP usage.

Available tools

The Harmonic MCP server provides tools organized into the following categories:

Enrichment tools

Get rich info about companies, people, and investors. Deal data is available as an add-on; contact your account team for access.

Search tools

Find companies and people using natural language queries or fast lookups by name, domain, linkedin URL, or email.

Lookup tools

Retrieve companies, people, or investors in bulk by ID or canonical URL.

Saved search tools

Get results from your saved searches across companies, people, and investors, including net-new results for subscribed searches.

Network mapping tools

Discover how your team is connected to specific companies or people.

List management tools

Create and manage lists of companies and people within Harmonic.

Custom data tools

Add and manage custom data on companies and people, both globally across your workspace and within specific lists.

Best practices

Read-only vs. write actions

Most tools in the Harmonic MCP server are read-only. Write tools, such as creating or updating lists, are also available, but Harmonic does not currently support any destructive operations. This documentation will be updated if that changes.

Harmonic follows the MCP standard for surfacing read-only hints in tool metadata, which means MCP-compatible clients like Claude and ChatGPT will natively prompt users for confirmation before executing write actions.

If you are building a custom MCP client, we recommend implementing human-in-the-loop (HITL) confirmation flows for write actions.

Example use cases

Example 1: Enrich a company

Prompt: "Get detailed information about Anthropic, including their funding, location, and founders."

Your AI assistant will likely use enrichment or search tools to retrieve comprehensive company data.

Example 2: Search for companies

Prompt: "Find fintech companies in New York that raised Series B funding in the last 6 months."

Your AI assistant will likely use search tools to find matching companies.

Example 3: Create a company list

Prompt: "Create a list called 'AI Startups' and add Anthropic, OpenAI, and Cohere to it."

Your AI assistant will likely use search tools to find company URNs, then list management tools to create the list and add companies to it.

Example 4: Map your network

Prompt: "Show me which people on my team are connected to Stripe."

Your AI assistant will likely use network mapping tools to identify team connections.

Privacy and data handling

Data collection and usage

The Harmonic MCP server acts as a secure proxy between your AI assistant and the Harmonic API. Here's how we handle your data:

Authentication tokens: Your JWT tokens are used only to authenticate requests to the Harmonic API. They are not stored, logged, or shared with third parties.
OAuth state: Temporary OAuth state is stored in Google Cloud Datastore with a 10-minute expiration for the OAuth flow only.
Request data: Tool parameters and responses are passed through the server but not stored or logged.
No conversation data: The server does not collect or store conversation data from your AI assistant.

Privacy policy

For complete information about how Harmonic collects, uses, and retains data, please see our Privacy Policy.

Security

OAuth 2.0: The server uses OAuth 2.0 with Firebase JWT tokens signed using certificates from Google's recognized certificate authority
HTTPS: All communications are encrypted via HTTPS
Authentication Required: All requests require valid authentication (JWT token)

Troubleshooting

"Unauthorized" error

Possible causes:
- OAuth authentication failed or was cancelled
- Token expired and refresh failed
- OAuth callback URL not properly configured
Solutions:
- Check that you completed the OAuth flow in your browser
- Verify your Harmonic account is active and accessible
- Try removing and re-adding the MCP server configuration to trigger a new OAuth flow
- Check your MCP client logs for OAuth errors

Tools not appearing

Possible causes:
- MCP server not properly configured
- Authentication failed
- Client needs restart
Solutions:
- Verify your configuration is correct
- Check authentication credentials
- Restart your MCP client after configuration changes

Rate limiting

If you encounter rate limit errors:
- The Harmonic API has rate limits to ensure fair usage
- Wait a moment before making additional requests
- Consider using field groups to request only needed data