How to Use the Harmonic MCP in LangChain

Q: How do I use Harmonic with LangChain?

Install the adapters with pip install langchain-mcp-adapters langgraph. You then configure MultiServerMCPClient to point to this MCP Server endpoint and pass the tools into your ReAct agent.

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Connect Harmonic MCP to LangChain

Create your Vinkius account to connect Harmonic to LangChain and route execution through our secure gateway. The platform manages server hosting, runtime updates, and security layers. Configuration requires no manual server provisioning.

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Setup Harmonic with LangChain

Ask AI about this MCP

ChatGPT

Claude

Perplexity

LangChain ReAct agents for deal flow

Your LangChain agent uses Harmonic to execute industry theses. It triggers `search_startups` to pull a list of companies matching specific headcount and location filters. The output immediately becomes the input for the next step in your chain. The agent runs `enrich_company` on each result to pull firmographics, then hits `list_funding_rounds` to verify their last raise. You get a fully vetted deal sheet instead of raw JSON.

Traceable founder background checks

Harmonic prevents hallucinated professional histories. Passing `enrich_person` to your ReAct pipeline forces the agent to fetch live social signals and work experience directly from the source. Every step is fully visible in LangSmith. You see exactly what inputs the agent passed to `list_traction_signals` and how much latency the API introduced to your workflow.

Harmonic MCP Server portfolio mapping

Harmonic maps competitor syndicates in seconds. Your agent calls `search_investors` to find active angels in your sector instead of scraping crunchbase manually. It then loops through the results using `get_investor_portfolio`. The chain aggregates the entire network into a single Markdown report, complete with headcount statistics via `get_company_stats`.

Setup guide

Set up Harmonic MCP in LangChain

Prerequisites

Python 3.10+ installed
langchain-mcp-adapters + langgraph packages
Active Vinkius subscription with a valid endpoint token

1

Install dependencies
Run pip install langchain-mcp-adapters langgraph langchain-openai. The MCP adapters package converts MCP tools into native LangChain BaseTool objects.
2

Connect via HTTP transport
Use MultiServerMCPClient with "transport": "http" pointing to your Vinkius endpoint. Replace [YOUR_TOKEN_HERE] with your token from cloud.vinkius.com.
3

Create a ReAct agent
Pass the discovered tools to create_react_agent() from LangGraph. The agent automatically routes Harmonic tool calls through the MCP protocol.
4

Run with any LLM
Swap ChatOpenAI for ChatAnthropic, ChatGoogleGenerativeAI, or any LangChain-compatible model. The MCP tools work identically across all providers.

agent.py

from langchain_mcp_adapters.client import MultiServerMCPClient
from langgraph.prebuilt import create_react_agent
from langchain_openai import ChatOpenAI

async with MultiServerMCPClient({
    "harmonic-mcp": {
        "transport": "http",
        "url": "https://edge.vinkius.com/[YOUR_TOKEN_HERE]/mcp",
    }
}) as client:
    tools = client.get_tools()

    agent = create_react_agent(
        ChatOpenAI(model="gpt-4o"),
        tools,
    )
    result = await agent.ainvoke({
        "messages": "List recent Harmonic transactions"
    })
    print(result["messages"][-1].content)

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Independent Platform Disclaimer: Vinkius is an independent platform and is not affiliated with, endorsed by, sponsored by, verified by, or otherwise authorized by Harmonic. All third-party trademarks, logos, and brand names are the property of their respective owners. Their use on this website is strictly for informational purposes to identify service compatibility and interoperability.

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Common questions about Harmonic MCP in LangChain

Install the adapters with `pip install langchain-mcp-adapters langgraph`. You then configure `MultiServerMCPClient` to point to this MCP Server endpoint and pass the tools into your ReAct agent.

Yes. Your agent can take the output of a broad search and automatically feed those domains into targeted enrichment tools.

LangSmith handles all observability. You can track exactly how many calls your agent makes to the endpoints and monitor the associated latency.

Your chain can handle asynchronous jobs. The agent simply calls `get_enrichment_status` in a loop until the data is ready, keeping MCP connections stable.

Harmonic touches firmographics, funding, and social signals. The MCP integration operates statelessly, passing raw JSON directly to your local LangChain environment. Vinkius sandboxes the connection so no proprietary deal flow leaks back to the provider.

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