libofcongress-mcp-server

An MCP server that enables agents to search Library of Congress digital collections, browse Chronicling America newspapers with full OCR text, and look up LC Subject Headings. It supports STDIO or Streamable HTTP protocols and provides tools for searching items, retrieving metadata, searching newspapers, and browsing curated collections.

Package and access

Local package with source-attributed installation metadata. Koskamo does not execute packages during review.

Community listingLocal stdioSource reviewed; not executedPublished by cyanheads

Vendor documentation

What you can do with it

Search LOC digital collections by keyword with filters
Browse Chronicling America newspapers with full OCR text
Look up LC Subject Headings by keyword
Retrieve full metadata for specific LOC digital items

Source and maintenance

Community listingRegistry 0.5.1

mcp-registry: io.github.cyanheads/libofcongress-mcp-server@0.5.1 Source repository

Maintenance checked: Oct 31, 2026, 10:27 PM UTC

Packages and installation

Source-provided package data. Koskamo has not executed or live-probed this package.

@cyanheads/libofcongress-mcp-server 0.5.1

npmnpx

@cyanheads/libofcongress-mcp-server package definition

{
  "version": "0.5.1",
  "transport": "stdio",
  "identifier": "@cyanheads/libofcongress-mcp-server",
  "runtimeHint": "npx",
  "registryType": "npm",
  "registryBaseUrl": "https://registry.npmjs.org",
  "environmentVariables": [
    {
      "name": "LOC_USER_AGENT",
      "format": "string",
      "default": "libofcongress-mcp-server/0.5.1",
      "description": "User-Agent header sent with LOC API requests. LOC recommends a descriptive value for polite access."
    },
    {
      "name": "LOC_REQUEST_DELAY_MS",
      "format": "string",
      "default": "3100",
      "description": "Delay in milliseconds between LOC API requests to stay under the 20 req/min rate limit."
    },
    {
      "name": "MCP_LOG_LEVEL",
      "format": "string",
      "default": "info",
      "description": "Sets the minimum log level for output (e.g., 'debug', 'info', 'warn')."
    },
    {
      "name": "MCP_SESSION_MODE",
      "format": "string",
      "default": "stateless",
      "description": "HTTP session mode: auto, stateful, or stateless."
    }
  ]
}

Tools

Reported by the attributed source; not independently observed by Koskamo.

No tool definitions available.

Connect from your client

Each snippet configures the same source-provided package; replace placeholders before use.

This server is operated by the named third party. Listing and endpoint checks are not an endorsement or a security audit. Review the operator's permissions, terms, and data handling before connecting. How listings are checked and corrected.

Cursor

Merge this local stdio configuration, replace every placeholder environment value, and restart Cursor. Koskamo has not executed this package.

Cursor configuration

{
  "mcpServers": {
    "libofcongress-mcp-server": {
      "command": "npx",
      "args": [
        "-y",
        "@cyanheads/libofcongress-mcp-server@0.5.1"
      ],
      "env": {
        "LOC_USER_AGENT": "<YOUR_LOC_USER_AGENT>",
        "LOC_REQUEST_DELAY_MS": "<YOUR_LOC_REQUEST_DELAY_MS>",
        "MCP_LOG_LEVEL": "<YOUR_MCP_LOG_LEVEL>",
        "MCP_SESSION_MODE": "<YOUR_MCP_SESSION_MODE>"
      }
    }
  }
}

Cline

Merge this local stdio configuration, replace every placeholder environment value, and restart Cline. Koskamo has not executed this package.

Cline configuration

{
  "mcpServers": {
    "libofcongress-mcp-server": {
      "command": "npx",
      "args": [
        "-y",
        "@cyanheads/libofcongress-mcp-server@0.5.1"
      ],
      "env": {
        "LOC_USER_AGENT": "<YOUR_LOC_USER_AGENT>",
        "LOC_REQUEST_DELAY_MS": "<YOUR_LOC_REQUEST_DELAY_MS>",
        "MCP_LOG_LEVEL": "<YOUR_MCP_LOG_LEVEL>",
        "MCP_SESSION_MODE": "<YOUR_MCP_SESSION_MODE>"
      }
    }
  }
}

VS Code

Merge this local stdio configuration, replace every placeholder environment value, and restart VS Code. Koskamo has not executed this package.

VS Code configuration

{
  "servers": {
    "libofcongress-mcp-server": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "@cyanheads/libofcongress-mcp-server@0.5.1"
      ],
      "env": {
        "LOC_USER_AGENT": "<YOUR_LOC_USER_AGENT>",
        "LOC_REQUEST_DELAY_MS": "<YOUR_LOC_REQUEST_DELAY_MS>",
        "MCP_LOG_LEVEL": "<YOUR_MCP_LOG_LEVEL>",
        "MCP_SESSION_MODE": "<YOUR_MCP_SESSION_MODE>"
      }
    }
  }
}

Claude Desktop

Merge this local stdio configuration, replace every placeholder environment value, and restart Claude Desktop. Koskamo has not executed this package.

Claude Desktop configuration

{
  "mcpServers": {
    "libofcongress-mcp-server": {
      "command": "npx",
      "args": [
        "-y",
        "@cyanheads/libofcongress-mcp-server@0.5.1"
      ],
      "env": {
        "LOC_USER_AGENT": "<YOUR_LOC_USER_AGENT>",
        "LOC_REQUEST_DELAY_MS": "<YOUR_LOC_REQUEST_DELAY_MS>",
        "MCP_LOG_LEVEL": "<YOUR_MCP_LOG_LEVEL>",
        "MCP_SESSION_MODE": "<YOUR_MCP_SESSION_MODE>"
      }
    }
  }
}

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