Matrix MCP server

Matrix for Claude Code

Claude Code can grep code, but it cannot search PDFs, Word files, scans or charts by meaning. Matrix gives it a local semantic index over your document folders, with citations to file, page and passage, cross-references between provisions and tables over many documents — everything runs on your computer, and Claude Code itself is the language model, so no extra model or API key is needed. DEMO.md compares it with Claude Code alone on 442 and on 1,592 pages of public documents.

Why use it

Measured twice, Claude Code alone vs. with the plugin (DEMO.md has the numbers, the questions and the right answers): on 442 pages of EU regulations and a report (4 questions, 2 runs each), and on 1,592 pages in 14 documents in four languages (version 0.2.3, 4 questions, 1 run each).

• Less effort on large document sets. 442 pages: on average 42 s instead of 126 s per question (about 3×; 2–4× depending on the question), with less than half the tool calls (9.5 instead of 21.4) and less than half the input tokens (303 k instead of 651 k). 1,592 pages: 35 % less time (117 s instead of 180 s for the four questions), 34 % fewer input tokens (405 k instead of 615 k), 60 % fewer output tokens and half the rounds. The gain is largest for a question about one provision asked in other words or another language, and smallest where the answer is spread over several acts (almost none: Claude searches once per act either way).
• Index once, ask many times. Indexing runs once on your computer and costs no Claude tokens; the index stays across sessions and follows its folder by itself. Every further question about the same documents is then faster and uses fewer tokens (DEMO.md). This pays off when there are many or long documents, further questions about the same set are likely and answers should come with evidence — for example contracts, regulations, project files, technical manuals, studies, minutes or reports. For a one-off question Claude may search the files itself, and says so when an answer has no evidence from your files.
• Citations with file, article and passage, checked against the text. Every answer in both tests named the right document, article and passage. Two page numbers on the large set were one page off, where a passage runs over a page break (known, not yet fixed); Claude Code alone had exact pages.
• Finds paraphrases, scans and charts. Search is by meaning, so a question in other words than the text still finds the provision, and a value that exists only in a chart is found on the chart page. On 30 test questions the right place was first for 17 (12 in 0.2.2) and among the first five for 27 (19 before), with the optional re-ranking model; one search result is about 1,160 tokens instead of 5,500. In folders that mix languages, search works best in the documents' language; the skills tell Claude to search in it too.
• Tables over many documents. One question put to every document or passage, as a table with a source per cell.
• Everything local, no extra model access. Index and search run on your computer; Claude Code itself is the language model, so no second model or API key is needed.
• Claude Code alone answered all questions correctly too (8/8 and 4/4); with the plugin one answer in the first runs of the 442-page test was wrong (a chart label too small to read), fixed in the ask skill, then 4/4 correct. The gain is effort, not correctness.

It brings little for small, well-structured collections that Claude Code reads quickly anyway: one short document is answered just as well without it, and indexing costs minutes once per folder.

Install

Requires a Mac with Apple silicon (macOS, arm64) and Node.js 18 or later (for npx) for now.

claude plugin marketplace add matthiasnordwig/matrix-mcp
claude plugin install matrix@matrix-mcp

Shortened. The full README is on GitHub.