Groundlink
Give Claude, Cursor, and other MCP hosts one groundlink_search tool that returns verified, source-bearing results instead of unsupported guesses. 100 free queries per key, then a tenth of a cent per query.
Documentation
Groundlink MCP Server
Use Groundlink's cited web-search results from any Model Context Protocol (MCP)
host. The server exposes one focused tool, groundlink_search, which sends a
query to Groundlink and returns source-bearing results (title, url,
snippet, and source) for the model to use when it needs evidence rather
than a guess.
Groundlink currently combines Wikipedia and DuckDuckGo results. Each Groundlink API key includes 100 free test queries; after that, prepaid usage is $0.001 per query (one credit per query).
Package:
groundlink-mcp@0.1.1is published on npm. Source: https://github.com/ohhavefun/groundlink
- Live API documentation: https://9ea69cec60fa01f65bbb647a092bcbb4.ctonew.app/docs
- Pricing and credits: https://9ea69cec60fa01f65bbb647a092bcbb4.ctonew.app/pricing
This repository is the home of Groundlink's official developer integrations. There are two, both maintained here:
| Integration | What it is | Install |
|---|---|---|
| groundlink-mcp (MCP server) | Exposes Groundlink to any MCP host (Claude, Cursor, …) | npm install -g groundlink-mcp (also on the official MCP registry as io.github.ohhavefun/groundlink) |
| langchain-groundlink (Python/LangChain) | A GroundlinkSearchTool for Python agents | pip install "langchain-groundlink @ git+https://github.com/ohhavefun/groundlink#subdirectory=langchain-groundlink" |
Both use the same free trial keys (100 queries) from the Groundlink onboarding, then prepaid usage at $0.001/query.
langchain-groundlink (Python / LangChain)
Use Groundlink's cited search from any Python agent or BaseTool pipeline.
The tool returns source-bearing results (title, url, snippet, source)
so your agent answers from evidence and can cite it.
Install from GitHub (the package is intentionally not on PyPI):
pip install "langchain-groundlink @ git+https://github.com/ohhavefun/groundlink#subdirectory=langchain-groundlink"
Quick usage (10 seconds): get a free key from the docs, then:
from langchain_groundlink import GroundlinkSearchTool
tool = GroundlinkSearchTool(api_key="glk_your_trial_key") # or export GROUNDLINK_API_KEY
result = tool.invoke({"query": "Who was Ada Lovelace?"})
print(result)
Full usage, configuration, and error handling are in
langchain-groundlink/README.md.
Groundlink MCP Server
Use Groundlink's cited web-search results from any Model Context Protocol (MCP) host below.
| Field | Value |
|---|---|
| Tool name | groundlink_search |
| Input | { query: string, max_results?: number } |
max_results | 1–10; default 5 (or GROUNDLINK_MAX_RESULTS) |
| Output | JSON: { query, results: [{ title, url, snippet, source }], meta } |
Use it for factual questions where the host should return URLs/sources with its answer. The MCP server is deliberately thin: it forwards the query to the Groundlink HTTPS API and returns the API response over MCP stdio.
Install and run
You need a Groundlink API key (glk_...). Ask the Groundlink operator for one
or obtain one through the Groundlink onboarding flow.
npm install -g groundlink-mcp
export GROUNDLINK_API_KEY=glk_your_key_here
groundlink-mcp
Alternatively, an MCP host can execute the package without a global install:
npx -y groundlink-mcp
The process uses stdio; it does not open an HTTP port or print normal output to stdout. MCP hosts should launch it rather than running it interactively.
Configuration
| Variable | Required | Default | Meaning |
|---|---|---|---|
GROUNDLINK_API_KEY | Yes | — | API key used for every Groundlink request. |
GROUNDLINK_BASE_URL | No | Groundlink live URL | Override only for a compatible deployment. |
GROUNDLINK_MAX_RESULTS | No | 5 | Default results per tool call; capped at 10. |
Claude Desktop configuration
Add this entry to Claude Desktop's MCP configuration file and restart Claude Desktop. Keep the API key private: do not commit it to a repository or share the configuration file.
{
"mcpServers": {
"groundlink": {
"command": "npx",
"args": ["-y", "groundlink-mcp"],
"env": {
"GROUNDLINK_API_KEY": "glk_your_key_here"
}
}
}
}
If the package is installed globally, use "command": "groundlink-mcp" and
omit args. For hosts that need an absolute executable path, point command
at the installed groundlink-mcp binary.
What happens on errors
- Missing
GROUNDLINK_API_KEY: the server exits at startup with a clear setup error. - API key rejected (401): returned to the MCP host as a tool error; correct the key rather than retrying.
- No remaining free or prepaid credits (402): returned as a tool error; fund the key before another search.
- Search-source outage (502): returned as a tool error; a short retry may help.
Marketplace description
Groundlink — cited web search for MCP. Give Claude, Cursor, and other MCP
hosts one groundlink_search tool that returns source-bearing results instead
of unsupported factual guesses. Every key starts with 100 free tests, then
usage is $0.001 per query through prepaid credits.
Development and release checks
bun install
bun run typecheck
bun run build # emits executable dist/index.js
bun run test # MCP stdio smoke test
npm run pack:check # inspect the npm tarball without publishing
The npm package intentionally ships only the compiled dist/ runtime, this
README, and npm's required package metadata. Source and smoke tests stay out of
the tarball.