Fixing LLM Hallucinations with MCP Servers

January 16, 2026

The speed of AI is humbling. New frameworks drop every week, and the knowledge cutoffs of even the best models (Gemini, Claude 3.5 Sonnet) can't keep up.

I ran into this wall hard while building "Say Play" (my agentic video platform). I was trying to use the latest LangChain features, but my Agentic IDE kept hallucinating deprecated syntax. It didn't know the new APIs existed yet.

The solution wasn't better prompting—it was Context Injection via MCP.

The Problem: Stale Context

I love building with "Antigravity" (my IDE setup), but it struggled with recent coding packages. It would confidently write code that was correct 3 months ago but broken today.

The Fix: Model Context Protocol (MCP)

I discovered that LangChain offers an MCP Server for its documentation. Instead of pasting docs into the chat manually, I configured my IDE to fetch the latest docs dynamically.

Here is the config I added to my MCP settings:

{
    "mcpServers": {
        "langchain-docs": {
            "serverUrl": "https://docs.langchain.com/mcp",
            "type": "sse"
        }
    }
}

The Result

Instantly, the hallucination stopped. The agent understood the new architecture patterns and generated up-to-date implementation code for my video composition agents.

If you are building with Agentic IDEs, stop relying on the model's training data for bleeding-edge frameworks. Hook up an MCP server.

Next up: I'm using this stack to build the rendering engine for Say Play. More on that in the next log.