Lego Oracle

What gregario/lego-oracle MCP server does

The gregario/lego-oracle MCP server gives an MCP-compatible client structured access to LEGO catalog data sourced from Rebrickable. Its dataset includes 26,339 sets, 61,702 parts, 275 colours, 16,646 minifigures, more than 1.4 million inventory entries, 35,757 part relationships, and 490 themes. The project is distributed under the MIT license.

Set queries can use names, themes, years, or piece counts. A set lookup returns inventory grouped by part category, minifigures, and its position in the theme hierarchy. Set comparison accepts two to four sets and reports differences such as piece count, release year, theme, minifigures, and shared parts.

Part-focused queries support names, categories, colours, and materials. Individual part records include available colours and mold or print variants, while inventory searches identify sets containing a part and can restrict results to a colour. Minifigure searches work by name and can return every set containing a selected figure.

How it works

The catalog is embedded during the build rather than fetched for each request. As a result, the server does not make network calls at runtime and does not require a Rebrickable API key. Rebrickable data is refreshed daily through GitHub Actions, and new npm releases are published when the source data changes.

Discovery tools cover the LEGO theme hierarchy and community alternate builds. Theme browsing can start at top-level themes or continue into sub-themes with set counts. MOC searches find alternate models that use the parts from a specified set.

Setup and configuration

The documented installation uses Node.js 18 or newer and the npm package:

npx -y lego-oracle

The server is configured as a local stdio MCP process. For Claude Desktop, Cursor, and Windsurf, the README shows an MCP entry using npx with -y lego-oracle as the arguments. No environment variables, credentials, or additional runtime configuration are documented.

For development, the repository uses npm install, npm run build, and npm test. The test command is documented as running 141 tests. Refreshing the source data requires npm run fetch-data followed by npm run build.

Tools and capabilities

The gregario/lego-oracle MCP server exposes these ten tools:

• search_sets, get_set, and compare_sets for set discovery, details, and side-by-side analysis.
• search_parts, get_part, and find_part_in_sets for part and colour-based catalog queries.
• search_minifigs and get_minifig for minifigure searches and appearance history.
• browse_themes for navigating themes and sub-themes.
• find_mocs for locating community alternate builds based on a set’s parts.

Limitations and notes

The server’s information is limited to the embedded Rebrickable catalog and its update schedule. Because data is packaged at build time, a newly changed catalog may require a newer npm release before it appears in results. The project states that LEGO is a trademark of the LEGO Group and that the project is not produced or endorsed by LEGO.

The gregario/lego-oracle MCP server is intended for catalog lookup and discovery. The supplied material does not document purchasing, inventory ownership, prices, set instructions, or live availability features.