Libofcongress MCP Server runs on your own machine — the client starts it, so there is no endpoint to ping. 98 installs a week from npm. Last commit 23 Aug 2026.
Search LOC digital collections, Chronicling America newspapers (full OCR), and LC Subject Headings.
Today is the operative word: we check Libofcongress MCP Server every 15 minutes and re-read its code on every release. Watch it and you find out the day that stops being true.
This server runs on your own machine — install it with the package manager and the client starts it for you. Package name taken from the official registry entry.
claude mcp add libofcongress-mcp-server -- npx -y @cyanheads/libofcongress-mcp-server
{
"mcpServers": {
"libofcongress-mcp-server": {
"args": [
"-y",
"@cyanheads/libofcongress-mcp-server"
],
"command": "npx"
}
}
}
[mcp_servers.libofcongress-mcp-server]
command = "npx"
args = ["-y", "@cyanheads/libofcongress-mcp-server"]
{
"mcpServers": {
"libofcongress-mcp-server": {
"args": [
"-y",
"@cyanheads/libofcongress-mcp-server"
],
"command": "npx"
}
}
}
{
"mcpServers": {
"libofcongress-mcp-server": {
"args": [
"-y",
"@cyanheads/libofcongress-mcp-server"
],
"command": "npx"
}
}
}
This one needs environment variables set before it will start:
LOC_USER_AGENT (User-Agent header sent with LOC API requests. LOC recommends a descriptive value for polite access.), LOC_REQUEST_DELAY_MS (Delay in milliseconds between LOC API requests to stay under the 20 req/min rate limit.), MCP_HTTP_HOST (The hostname for the HTTP server.), MCP_HTTP_PORT (The port to run the HTTP server on.), MCP_HTTP_ENDPOINT_PATH (The endpoint path for the MCP server.), MCP_AUTH_MODE (Authentication mode to use: 'none', 'jwt', or 'oauth'.), MCP_LOG_LEVEL (Sets the minimum log level for output (e.g., 'debug', 'info', 'warn').), MCP_SESSION_MODE (HTTP session mode: auto, stateful, or stateless.).
The author declared them in the registry entry; get the values from the project itself.
Crawl documentation sites into local corpora agents can search, read, and diff fully offline.
Exact document sections on demand for LLM agents: index in context, search, read, grep, neighbours.
Hybrid search over your local documents, with file and page citations. One binary, fully local.
Offline MCP server for local Qt 4.8, Qt 5, and Qt 6 documentation with full-text search.
MCP server for the Transkribus REST API — collections, documents, HTR/OCR, and models.
Auto-document vibe coding sessions - collect, summarize, and publish
Local-first document management and semantic search for AI coding agents
Connect AI assistants to Outline for document search, reading, and management
Answers built from our own checks of this server.