Catalyst evidence graph

What Catalyst evidence graph MCP server does

Catalyst evidence graph MCP server gives MCP-compatible clients access to a curated evidence graph covering compounds, supplements, nutrients, and foods studied in humans. Agents can look up findings associated with a compound or an outcome and inspect the supporting context rather than receiving an unsupported summary.

Each finding includes an evidence_strength level: strong, moderate, limited, very_limited, or insufficient. The level is computed from the underlying study. Results also provide the quoted sentence used as evidence, the paper, the studied population, the dose, and a permalink for verification.

The graph also includes relations drawn from reference databases, including targets, pathways, and reactions. These relations are labelled as hypotheses and should not be treated as reported study findings. Evidence strength is descriptive, not a recommendation or medical advice.

How it works

The hosted endpoint is available at https://catalystproject.ai/mcp using MCP over Streamable HTTP. It is read-only and does not require an account or API key. Clients connect directly to the endpoint, while this repository supplies client configuration, registry metadata, and extensions for selected environments.

The get_findings operation accepts an evidence_strength floor so callers can limit results to findings at or above a selected level. Since version 0.2.0, results use named evidence levels instead of letter grades. The former grade field and argument are no longer supported; requests that send grade receive an error identifying the replacement.

Setup and configuration

Add the server URL to an MCP client using its HTTP or custom-connector configuration. A generic configuration is:

{ "mcpServers": { "catalyst": { "url": "https://catalystproject.ai/mcp" } } }

Claude supports a custom connector, while Cursor and VS Code have client-specific setup options. Claude Code can install either the hosted server alone or the repository’s plugin, which also adds a skill for presenting evidence strength. Gemini CLI can install the repository as an extension. VS Code also provides an extension that registers the server with Copilot’s agent mode.

No environment variables, local database, API credential, or self-hosted process are required for the hosted service. The repository is MIT-licensed, while graph content follows the terms and source licenses documented by the project.

Tools and capabilities

The Catalyst evidence graph MCP server supports:

• Finding evidence associated with a compound or outcome.
• Filtering findings using an evidence_strength threshold.
• Returning study-derived evidence levels and verbatim supporting sentences.
• Providing paper, population, dose, and verification permalink details.
• Exposing target, pathway, and reaction relations from reference databases.
• Connecting through Claude, Cursor, VS Code, Gemini CLI, Claude Code, and other MCP clients that support the endpoint.

Limitations and notes

The service does not return products, prices, shopping links, or ranked recommendations. Its evidence levels describe support for a finding and should not be interpreted as advice about what to take.

The server stores no queries and has no accounts. Rate limits count calls per minute using the client name and a keyed hash of the network address rather than the address itself. The repository contains integrations and extensions, but the graph service itself is hosted at the project endpoint.