Context7
by upstash
Feeds AI the latest docs for libraries and frameworks before it answers, so code it writes does not use outdated, removed functions.
Computer or cloud★ 64,224MITUpdated today
Install
Crossref
Overview
Description from the maker (original English)
Search and retrieve scholarly metadata from the Crossref REST API
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 checksi1 of 1 passedChecked from public information; code not scanned yet
- UsageiNot measured yet★ –
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 on your computer
- Transport: stdio
- Category: Search & AI memory
Install
Pick the AI app you use, then copy the settings.
Before you install
- Basic checks: 1 of 1 passed
- Runs on your computer with your user’s permissions (files, network, apps).
- You fill in yourself:
CROSSREF_MAILTO
You need
- PyPIPython’s uv installed (for the uvx command)
Which app do you use?
Pick your app above. We remember it, so next time the button says “Install in …”.
Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json
{
"mcpServers": {
"crossref": {
"command": "uvx",
"args": [
"crossref-mcp-server"
],
"env": {
"CROSSREF_MAILTO": "your-value"
}
}
}
}Run this in your terminal
claude mcp add crossref --env CROSSREF_MAILTO=your-value -- uvx crossref-mcp-serverFill in the empty values before running it.
Or copy the settings yourself
Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json
{
"mcpServers": {
"crossref": {
"command": "uvx",
"args": [
"crossref-mcp-server"
],
"env": {
"CROSSREF_MAILTO": "your-value"
}
}
}
}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": {
"crossref": {
"type": "stdio",
"command": "uvx",
"args": [
"crossref-mcp-server"
],
"env": {
"CROSSREF_MAILTO": "your-value"
}
}
}
}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.
This one runs on your computer, and ChatGPT can only connect to servers on the internet. Pick another app.
Your choice stays on this device in a cookie; no account needed.
Values you fill in
CROSSREF_MAILTOenvYour email for Crossref polite pool (better rate limits, no key needed)
These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.
What it can do
Runs on your computer; the tool list appears in your AI app after you install it.
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 6, 2026
- ✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account SMABoundless, which owns the repo
- … 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
- – Not applicable
Endpoint responds
This one runs on your computer; there is no internet endpoint
- – Not applicable
Sign-in with OAuth
Runs on your computer and uses local settings instead
- … Not checked yet
No hidden instructions in tool descriptions
Runs on your computer; we can only read tool lists from internet endpoints
Compared with others in Search & AI memoryi
- More stars than 0% of the other 7247 servers in this category
- Published to the registry more recently than 20% of the other 7247 servers in this category
- Basic checks equal to or better than 100% of the other 7247 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 Crossref safe?
It passed 1 of 1 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 on your computer. Your AI app starts it when needed, and data does not pass through the maker’s servers (unless it calls an online service itself).
Is it still maintained?
The GitHub repo last changed –, and the latest version (1.0.0) reached the registry 4 months ago.
Which apps can use it?
Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Python (uv) on your computer.
What can I use instead?
In the same category: Context7, Codebase Memory, Exa
Alternatives
Servers in the same category from other makers, sorted by stars.
Reading a card:★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi
Codebase Memory
by DeusData
Codebase knowledge graph for AI agents — 162 languages, sub-ms queries, 99% fewer tokens.
Runs on your computer★ 48,148MITUpdated 20 days ago
Install
Exa
by exa-labs
Connect AI agents to Exa for web search, content fetching, and multi-step research.
Runs in the cloud★ 5,213MITUpdated last month
Install
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.
CrossRef MCP Server
An MCP (Model Context Protocol) server for searching and retrieving scholarly metadata from the CrossRef REST API — 150M+ records across all publishers and disciplines.
Built with FastMCP. No API key required.
Tools
| Tool | Description |
|---|---|
crossref_search | Search works by keyword with filtering by year, type, and sort options |
crossref_title_search | Search specifically by title for more precise matching |
crossref_author_search | Search for works by a specific author, optionally combined with keywords |
crossref_doi_lookup | Retrieve full metadata for a work by DOI |
crossref_journal_search | Search for journals by name |
crossref_journal_works | Get works published in a specific journal by ISSN |
crossref_funder_search | Search for funding organizations |
crossref_references | Get the reference list cited by a specific work |
crossref_export_ris | Export recent results as RIS (for Zotero, EndNote, etc.) |
crossref_export_bibtex | Export recent results as BibTeX |
Setup
1. Install
cd crossref-mcp-serverpython3 -m venv venv source venv/bin/activate pip install -r requirements.txt
2. Configure environment (optional)
CrossRef doesn't require an API key, but setting a mailto address gives you access to their faster "polite" API pool:
cp .env.example .envEdit .env with your email address
3. Add to Claude Desktop
Add this to your claude_desktop_config.json:
{"mcpServers": { "crossref": { "command": "/path/to/crossref-mcp-server/venv/bin/python", "args": ["/path/to/crossref-mcp-server/server.py"], "env": { "CROSSREF_MAILTO": "your.email@example.com" } } } }
Or if using Claude Code CLI:
claude mcp add crossref \/path/to/crossref-mcp-server/venv/bin/python \ /path/to/crossref-mcp-server/server.py \ -e CROSSREF_MAILTO=your.email@example.com
Usage examples
Once connected, you can ask Claude things like:
- "Search CrossRef for recent papers on transformer architectures"
- "Find works by Jane Smith on educational psychology from 2020-2024"
- "Look up the metadata for DOI 10.1038/nature14539"
- "Search for journals about machine learning"
- "Get the reference list for this paper and export as RIS for Zotero"
License
MIT