Connects Claude to the U.S. National Library of Medicine MeSH APIs
MeSH MCP
An experimental MCP (Model Context Protocol) server connecting Claude to the U.S. National Library of Medicine (NLM) Medical Subject Headings (MeSH) linked data APIs, built to investigate the potential of large language models in subject analysis and authority control.
What This Server Does
MeSH MCP connects Claude Desktop to the NLM MeSH APIs, allowing you to search and retrieve MeSH authority data directly within your AI-assisted cataloging workflow.
Once installed, you can ask Claude things like:
- "Search MeSH for terms related to osmotic stress"
- "Find the MeSH descriptor for CRISPR gene editing"
- "What is the scope note for this MeSH descriptor?"
- "Look up the full record for descriptor D011506"
The server handles all the API calls, parses the responses, and returns structured data Claude can reason about.
Who This Is For
- Catalogers and metadata staff using Claude Desktop who want AI-assisted subject description grounded in real MeSH vocabulary data
- Library and repository staff working with health sciences or biomedical research outputs — theses, datasets, grey literature — where MeSH is the preferred controlled vocabulary
- Developers integrating MeSH lookups into MCP-based systems
Tools
| Tool | Description |
|---|---|
search_mesh |
Search MeSH descriptors by label using the NLM lookup autocomplete endpoint. Supports startsWith (default), contains, and exact matching. Returns a list of {label, ui, uri} dicts. |
get_mesh_record |
Retrieve the full record for a MeSH descriptor by UI code or URI. Returns label, annotation (scope note), tree numbers, tree categories, broader descriptors, see-also cross-references, and qualifier count. |
get_mesh_qualifiers |
Retrieve the allowable subheading qualifiers for a descriptor (e.g. Diabetes Mellitus/therapy). Optionally includes per-qualifier indexing annotations. |
get_mesh_tree |
Retrieve the MeSH tree hierarchy for a descriptor: tree numbers, top-level category names, and immediate broader (parent) descriptors. |
Notes on Search Behaviour
search_mesh uses left-anchored matching by default (startsWith), which matches from the beginning of the heading label. Searching diabetes will find Diabetes Mellitus and related headings, but searching mellitus will not. When a startsWith search returns no results, use match="contains" to search anywhere in the label.
For highly specialized or emerging concepts without a direct MeSH equivalent — such as specific protein families or recently coined terminology — search with a broader parent term and review the returned hierarchy to identify the best available descriptor.
Use get_mesh_record to verify before assigning. Retrieve the full
record to confirm the scope note matches the intended concept,
particularly when multiple candidate terms are returned. Tree numbers
indicate where the term sits in the MeSH hierarchy and can guide
selection of broader or narrower terms.
Installation
Requirements
- Python 3.11 or later
- Claude Desktop (or another MCP-compatible host)
Install from GitHub
pip install git+https://github.com/YOUR_USERNAME/mesh-mcp.git
Install from a local clone
git clone https://github.com/YOUR_USERNAME/mesh-mcp.git
cd mesh-mcp
pip install -e .
On Windows with Anaconda, use Anaconda Prompt and add
--break-system-packages if prompted.
Claude Desktop Configuration
After installation, add the server to your claude_desktop_config.json.
Claude Desktop uses a restricted PATH that does not include the Python
bin directory, so the full path to the command is required.
To find your exact path, run the following in Terminal (Mac) or Anaconda Prompt (Windows):
- Mac:
which mesh-mcp - Windows:
where mesh-mcp
The examples below are illustrative only — your actual path will differ depending on your Python version and installation method.
Mac (example):
{
"mcpServers": {
"mesh": {
"command": "/Library/Frameworks/Python.framework/Versions/3.13/bin/mesh-mcp"
}
}
}
Windows/Anaconda (example):
{
"mcpServers": {
"mesh": {
"command": "C:\\Users\\username\\anaconda3\\Scripts\\mesh-mcp.exe"
}
}
}
Always replace the path with the actual output of the which or where
command on your machine.
Finding your config file:
- Mac:
~/Library/Application Support/Claude/claude_desktop_config.json - Windows:
%APPDATA%\Claude\claude_desktop_config.json
After editing the config, quit Claude Desktop completely and reopen it. The MeSH tools will be available in your next conversation.
Verifying the installation
Once Claude Desktop is open, ask: "What cataloger tools do you have available?" — you should see all four MeSH tools listed.
Troubleshooting
Tools not appearing in Claude Desktop
Tools (4)
search_meshSearch MeSH descriptors by label using the NLM lookup autocomplete endpoint.get_mesh_recordRetrieve the full record for a MeSH descriptor by UI code or URI.get_mesh_qualifiersRetrieve the allowable subheading qualifiers for a descriptor.get_mesh_treeRetrieve the MeSH tree hierarchy for a descriptor.Configuration
{"mcpServers": {"mesh": {"command": "/path/to/mesh-mcp"}}}