Agent-Native Calendar
Agent-Native Google Calendar - manage events, sync, and public booking
Runs in the cloud
Metis Check
Overview
Description from the maker (original English)
Checks an answer's citations at the registries that issue them. Every check files a signed report.
PopNx MCP’s three pillars
These three are never merged into one score: opinions, measurements and popularity are different things.
- User voiceiNo reviews yetReviews open together with accounts in a later step
- Our basic checksi3 of 3 passedChecked from public information; code not scanned yet
- UsageiVery new★ –
What you can do with it
We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.
- Connection: Runs in the cloud
- Transport: Streamable HTTP
- Category: Docs, sheets & office work
Install
Pick the AI app you use, then copy the settings.
Before you install
- Basic checks: 3 of 3 passed
- Runs on the maker’s server: what you ask it goes through their server.
- The registry lists no key to fill in.
You need
- Runs in the cloudNothing to install; it connects over the internet
Which app do you use?
Pick your app above. We remember it, so next time the button says “Install in …”.
Works in Claude on the web, desktop and mobile:
- Open Settings → Connectors
- Press Add custom connector
- Paste the address below and press Add
- If it asks you to sign in, sign in with the maker
https://check-api.metisfoundry.com/mcp/checkRun this in your terminal
claude mcp add --transport http metis-check https://check-api.metisfoundry.com/mcp/checkOr copy the settings yourself
Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json
{
"mcpServers": {
"metis-check": {
"url": "https://check-api.metisfoundry.com/mcp/check"
}
}
}Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.
Or copy the settings yourself
Paste into .vscode/mcp.json in your project
{
"servers": {
"metis-check": {
"type": "http",
"url": "https://check-api.metisfoundry.com/mcp/check"
}
}
}Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.
ChatGPT connects only to servers on the internet:
- Open ChatGPT on the web → Settings → Connectors (Apps)
- Press Create or Add (some plans need Developer mode under Advanced first)
- Paste the address below, give it a name and save
- If it asks you to sign in, sign in with the maker
https://check-api.metisfoundry.com/mcp/checkMenu names can differ slightly by plan and over time.
Your choice stays on this device in a cookie; no account needed.
These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.
What it can do
The server asks you to sign in before it lists its tools.
Basic checksi
We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 10, 2026
- ✓ Pass
Maker matches the repo
The registry name was verified against the domain check-api.metisfoundry.com (the registry checks domain ownership)
- … Not checked yet
Still maintained
We have not read this repo from GitHub yet
- … Not checked yet
Has a licence
We have not read this repo from GitHub yet
- ✓ Pass
Endpoint responds
Responded in 294 ms (HTTP 401)
- ✓ Pass
Sign-in with OAuth
Declares OAuth sign-in, so your AI app can take you to log in
- … Not checked yet
No hidden instructions in tool descriptions
Not checked yet; we read the tool list when we check the endpoint
Compared with others in Docs, sheets & office worki
- More stars than 0% of the other 3650 servers in this category
- Published to the registry more recently than 69% of the other 3650 servers in this category
- Basic checks equal to or better than 100% of the other 3650 servers in this category
Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.
Common questions
Is Metis Check safe?
It passed 3 of 3 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.
What keys or codes does it need?
The registry does not list a required key, though some servers ask you to sign in on first use.
Does it run on my computer or in the cloud?
It runs in the maker’s cloud. Connect over the internet with nothing to install, but what you send passes through the maker’s servers.
Is it still maintained?
The GitHub repo last changed –, and the latest version (1.0.0) reached the registry 14 days ago.
Which apps can use it?
Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. It connects by URL, so apps that accept remote MCP servers work too, such as ChatGPT in developer mode.
What can I use instead?
In the same category: Agent-Native Calendar, Excel MCP Server, MCP Server for Excel
Alternatives
Servers in the same category from other makers, sorted by stars.
Reading a card:↓ Downloads per weeki★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi
Excel MCP Server
Lets AI create and edit Excel files itself, including formulas, charts and PivotTables, without Excel installed.
Runs on your computer
MCP Server for Excel
Excel automation for AI - Sheets, Power Query, DAX, VBA, Tables, Ranges and more. Windows only.
Runs on your computer
README from the maker
Open the README
Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.
Metis Check
The check every cited AI answer needs before you rely on it. A citation that looks complete and points to nothing costs a correction, a retraction or a sanction. Metis Check asks the registries that issue each identifier whether it exists and what it says. DOI, PubMed, arXiv, ORCID, ROR, ISBN, LEI, ISIN, CUSIP, SEC CIK, EIN, NPI, UK company numbers, domains and more. Each identifier comes back in exactly one of four states: settled true, settled false, not decidable (a person decides) or unreachable (a delay, not evidence). Every check ends in a signed report with its own id, a PDF and a recheck button anyone can press.
By Metis Foundry. One account covers ChatGPT, Codex, Claude, Claude Code, Cursor and VS Code. Every account starts with 5 checks a month; plans.
*A real report: three identifiers settled true, one settled false. Open it and press Recheck.*
Install
| Client | How |
|---|---|
| Claude (web, desktop, mobile) | Settings → Connectors → add a connector by URL: https://mcp.metisfoundry.com/mcp. Once Metis Check is listed in the connectors directory, choose it there. |
| Claude Code | /plugin marketplace add MetisFoundry/metis-plugins then /plugin install metis-check@metis, or claude mcp add --transport http metis-check https://mcp.metisfoundry.com/mcp |
| Codex CLI | codex plugin marketplace add MetisFoundry/metis-plugins then codex plugin add metis-check@metis |
| ChatGPT | The Metis Check plugin is submitted to the OpenAI directory. Until it is listed: Settings → Connectors → add by address https://check-api.metisfoundry.com/mcp/check |
| Cursor | Add to Cursor |
| VS Code | Add to VS Code (web redirect), or code --add-mcp '{"name": "metis-check", "type": "http", "url": "https://check-api.metisfoundry.com/mcp/check"}' |
| Any MCP client | Remote server https://check-api.metisfoundry.com/mcp/check (OAuth sign-in; a free account is created on first connection). Registry name com.metisfoundry/metis-check. |
Sign in or create a free Metis account when the client asks.
Try it in one click
The prompt asks Metis Check to check four references, one of them invented. The invented one comes back settled false, with the registry that said so.
What you get
- Four states, nothing hidden: settled true, settled false, not decidable, unreachable, and a not-checked list with the reason for each.
- A report that rechecks without Metis: every line carries the registry query and the SHA-256 of the registry's answer; signed JSON and a PDF.
- Shareable: anyone with the link can open the report and press Recheck; the registries are asked again, live.
- Private: passages are never stored, only the identifiers, their positions and a hash. Metis never asks for conversation history.
- Honest scope: Metis Check establishes that an identifier is registered and what the registry says. It does not decide whether a paper supports a claim.
Plans
Free: 5 checks a month. Pro: $29 a month (or $276 a year), 2,000 checks, case law included. Team: $249 a month (or $2,388 a year), 15,000 checks, 5 seats. Checks that cannot be settled cost nothing. Details: https://check-api.metisfoundry.com/check/plans
Repository layout
.agents/plugins/marketplace.json— Codex marketplace (metis); plugin inplugins/metis-check.claude-plugin/marketplace.json— Claude Code marketplace (metis); plugin manifest inplugins/metis-check/.claude-pluginplugins/metis-check/.codex-plugin/plugin.json— Codex plugin manifest (iconassets/icon-codex.png)server.json— official MCP Registry manifestPUBLISH.md— how the listings are published
Support and license
hello@metisfoundry.com. Proprietary: the files in this repository are not open source. You may install and use them, unmodified, with the Metis Check service, and plugin directories may mirror the unmodified plugin bundle so users can install it (LICENSE, NOTICE.md).