Keystone MCP Server

by srikarmk Your server? Claim it

not responding

Keystone is listed as active in the registry but did not answer our last check. It exposes 3 tools. Last commit 22 Oct 2026.

What an arXiv paper builds on, disputes and assumes, read verbatim from its LaTeX. No LLM.

Uptime history 6 days of history · worst day 6%

6 days agonow

13.2%

Uptime 24h

12 of 91 checks

Tools

read from the server

651 ms

Response time

average over 24h

Stars

last commit 22 Oct 2026

Keystone does not always answer

Over the last week it answered 16.8% of our checks. We check every 15 minutes, so you hear about the next outage within the hour — not from your users.

Connect this server

Endpoint below is the one we actually reach during checks — not the one copied from a README. Last verified 11 min ago.

Claude Code Claude Desktop Codex Cursor VS Code

run in your terminal

claude mcp add keystone --transport http https://keystone-research.vercel.app/api/mcp

Settings → Connectors → Add custom connector, then paste this address

https://keystone-research.vercel.app/api/mcp

~/.codex/config.toml

[mcp_servers.keystone]
url = "https://keystone-research.vercel.app/api/mcp"

.cursor/mcp.json

{
  "mcpServers": {
    "keystone": {
      "url": "https://keystone-research.vercel.app/api/mcp"
    }
  }
}

.vscode/mcp.json

{
  "servers": {
    "keystone": {
      "type": "http",
      "url": "https://keystone-research.vercel.app/api/mcp"
    }
  }
}

Available tools 3

Read directly from the server with tools/list, grouped by what they act on. If a tool disappears, we record the date.

disagreements

list_disagreements

Every sentence in the library where a paper says prior work is wrong, or puts itself beside it to win. Small on purpose — disagreement is rare and concentrated, and the whole set is readable.

library

search_library

Search 2497 readings taken from 234 arXiv papers' LaTeX source: citation stances (adopts, extends, disputes, measures against) and stated assumptions. Matches on the quoted sentence, the cue phrase that decided it, and the work cited. Returns the sentence verbatim with a link to the exact line.

paper

read_paper

Everything Keystone reads out of one arXiv paper: what it adopts, extends, disputes and measures against, and the assumptions it states with a citation, its own evidence, or nothing at all. Works for any paper on arXiv that ships LaTeX source — one outside the library is parsed on demand, which takes a few seconds. Nothing is summarised or inferred; every line is the paper's own.

Endpoints

URL	Transport	State	Latency	Checked
https://keystone-research.vercel.app/api/mcp	streamable-http	answering	42 ms	11 min ago

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same job, measured the same way

disputes.online

by disputes

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4 tools answering

LegendKeeper

by chase-roohms

Read and build LegendKeeper worlds from AI assistants: wiki pages, maps, timelines, facts and tags.

274 installs/wk local only

passmcp

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Evaluate an MCP server with passmcp and verify its attestations, from inside the agent. Read-only.

local only

Apex by DRIP: A/B testing for online shops

by drip-apex

A/B testing for online shops. Read results, build and preview test variations from chat.

answering

ResuStack

by resustackapp

Build, version and render resumes as PDFs from Claude or any MCP client.

answering

Web Fetch

by pipeworx-io

web-fetch — fetch ONE public URL live from its origin, verbatim.

43 tools answering

BuildBatch

by co-buildbatch

UK DIY shopping lists for one room: paint, wallpaper, tiles, flooring and more, in real packs.

4 tools answering

Crates Io MCP

by mrfentmen

Look up Rust crates, versions, and downloads from crates.io. No key required.

698 installs/wk local only

Keystone — questions

Answers built from our own checks of this server.

What can Keystone do?

It exposes 3 tools, read directly from the server on our last check. Among them: list_disagreements, read_paper, search_library. The full list with descriptions is on this page — we take it from the server itself via tools/list, not from a README. How MCP servers expose tools in the first place →

Is Keystone working right now?

We send a real MCP handshake every 15 minutes. Over the last 24 hours 12 of 91 checks got a reply (13.2%), average response time 651 ms. The bar chart above shows every period we have measured.

The registry lists Keystone as active — why does it not respond?

The official MCP registry stores what the author submitted; it does not verify that the server still runs. We check the endpoint ourselves, and this one does not answer. Catalogues that copy the registry without checking will show it as working.

How do I connect Keystone?

Copy the ready config from this page. We generate it for Claude Code, Claude Desktop, Codex, Cursor and VS Code, each in the form that client actually reads. It is a remote server, so there is nothing to install — the client connects to the address.

Does Keystone need an API key?

No. Keystone completed a full MCP handshake with us as an anonymous client and listed its tools without asking for anything. All 3 of them are readable on this page. This is what we observed, not what the docs claim.

How fast is Keystone?

It answers our handshake in 651 ms on average, which is faster than 18% of all working MCP servers we measure. That is on the slow side — worth knowing if the tool sits inside an interactive loop. The comparison comes from our own checks across the whole registry, every 15 minutes.

Is Keystone open source?

The code is open source: it is published under the MIT licence, written in Python and 0 stars on GitHub. The licence covers the code in the repository, not the hosted service at keystone-research.vercel.app, which runs on its operator's own terms.