defs
Routes giving access to standard fields and dictionaries used in Macrostrat
LABSCO SUMMARY
A coordinate turns into a named sequence of formations with dates attached.
The two location tools are the reason to install it: one question about a place comes back as an ordered stratigraphic history — basement, then each formation with its age range and depositional setting — rather than as a link to a map. The definitions tools matter more than they look, because geological queries fail on vocabulary; resolving the term first is what makes the unit lookup return the right thing. The map tiles are the weakest part and the author says so.
What it is
A client for the Macrostrat API — the geological database of stratigraphic columns, rock units, minerals and the geologic timescale. Eight tools, all reads, over a free and public API.
What you get
- Stratigraphic columns for any location worldwide — the layered geological history under a point, which is what a question about bedrock or age dating actually resolves to (find-columns).
- The rock units themselves: formations, lithology, mineral content and ages for a location, in a short or long response shape (find-units).
- The controlled vocabularies Macrostrat is built on, so a query uses the terms the database actually holds, plus a fast autocomplete over all definitions capped at 100 results (defs, defs-autocomplete).
- Information about a named mineral, looked up by one property (mineral-info).
- The geologic timescale, so a period name resolves to its bounds (timescale).
- Geological map tiles: convert a latitude and longitude to web-mercator tile x and y for a zoom level, then get the tile URLs from Macrostrat's tile server, defaulting to the carto scale that adapts detail to zoom (lat-lng-to-tile, map-tiles).
Requirements
Node.js 20 or newer, and nothing else — npx -y macrostrat-mcp over stdio, with no API key because the Macrostrat API is free and public.
Setup effort
One command — npx -y macrostrat-mcp
USE CASES
01
Finding out what a site is built on
Give the coordinates and get the units and columns beneath them, with ages and lithology.
02
Writing the geological background of a place
The column comes back as an ordered sequence you can narrate from oldest to youngest.
03
Getting the terminology right before querying
Resolve the formation or lithology name against Macrostrat's own dictionaries first.
04
Checking where a mineral occurs and what it is
Look it up by a single property rather than by free text.
05
Putting a geological map next to the data
Convert the coordinates to tile x and y first, then request the tile URLs at that zoom.
8 tools
Counted once with only startup setup. Other versions, modes or optional credentials may expose a different list.
defs-autocomplete
Quickly retrieve all definitions matching a query. Limited to 100 results
find-columns
Find geological stratigraphic columns, rock layers, and geological history for any location worldwide. Use for geology, bedrock, formations, age dating, and stratigraphic analysis.
find-units
Find geological rock units, formations, bedrock geology, and mineral information for any location worldwide. Use for geology questions, rock types, age dating, lithology, and geological analysis.
lat-lng-to-tile
Convert latitude/longitude coordinates to map tile coordinates (x, y) for a given zoom level. Uses the same web mercator projection as MapKit.
map-tiles
Get map tile URLs from the Macrostrat tiles server. Use lat-lng-to-tile tool first to get proper x,y coordinates. Defaults to 'carto' scale which automatically adapts detail level to zoom.
mineral-info
Get information about a mineral, use one property
timescale
Get information about a time period
BEFORE YOU INSTALL
What to know first
Tools you get
8 tools when we connected. Names use hyphens, such as find-units and lat-lng-to-tile, and all eight tools only read from a public API.
Requires
npx on PATH
Where it runs
Both documented clients run the server on your machine.
CONTEXT COST
Light Standing cost
Rated by the size of the 8 tool definitions that ride along on every turn, not by how many there are
INSTALLATION
Connect your client
Server setup
TERMINAL
npx -y macrostrat-mcpMCP Clients
Claude Desktop
CLAUDE DESKTOP · JSON
{
"mcpServers": {
"macrostrat": {
"command": "npx",
"args": [
"-y",
"macrostrat-mcp"
]
}
}
}Claude Code
CLAUDE CODE · TERMINAL
claude mcp add macrostrat -- npx -y macrostrat-mcp
