Interslavic MCP server

An MCP server and JSON API over the community Interslavic dictionary (Medžuslovjansky slovnik) — so LLMs read and write Interslavic, the constructed pan-Slavic auxiliary language designed for mutual intelligibility across the Slavic world (not a natural or historically attested tongue), with real dictionary words and correctly generated inflections rather than invented ones. Every entry carries a translation matrix into English and 11 Slavic languages; nouns, adjectives and verbs come with full, algorithmically generated paradigms. Read-only, fully offline.

MCP JSON API offline snapshot rate limited

Connect an MCP client

Remote streamable-HTTP endpoint — no auth, read-only: https://interslavic.valksor.com/mcp

Claude Code — CLI

claude mcp add --transport http interslavic https://interslavic.valksor.com/mcp

Cursor · Cline — remote url (~/.cursor/mcp.json) 

{
  "mcpServers": {
    "interslavic": { "url": "https://interslavic.valksor.com/mcp" }
  }
}

VS Code — .vscode/mcp.json 

{
  "servers": {
    "interslavic": { "type": "http", "url": "https://interslavic.valksor.com/mcp" }
  }
}

Claude Desktop · Windsurf · other stdio clients — bridge via mcp-remote (claude_desktop_config.json) 

{
  "mcpServers": {
    "interslavic": {
      "command": "npx",
      "args": ["-y", "mcp-remote", "https://interslavic.valksor.com/mcp"]
    }
  }
}

Claude Desktop only accepts command-based (stdio) servers in its config, so a bare url is rejected — the bridge above wraps the remote endpoint. On Pro/Team/Enterprise you can instead add it under Settings → Connectors → Add custom connector and paste https://interslavic.valksor.com/mcp.

Codex CLI — ~/.codex/config.toml 

[mcp_servers.interslavic]
command = "npx"
args = ["-y", "mcp-remote", "https://interslavic.valksor.com/mcp"]

Rule of thumb: clients with native streamable-HTTP/SSE support take the url directly (Claude Code, Cursor, Cline, VS Code); stdio-only desktop apps wrap it with npx -y mcp-remote https://interslavic.valksor.com/mcp.

Two tools

interslavic_search
query — Interslavic: any form, Latin or Cyrillic; English: the word itself.
Returns the translation matrix (English + 11 Slavic languages) plus inflection handles (full tables inline by default). An inflected query resolves to its headword automatically, and diacritics are optional — delati finds dělati. With search_language=eng the query is an English word and the result lists its Interslavic equivalents plus their entries.
interslavic_get_inflections
entry_id (the numeric word id), word_class (noun · adjective · verb) from a handle.
Returns the full generated paradigm — JSON grouped by category (noun cases, adjective gender forms with comparison, or the verb series), Markdown over MCP.

Or call the JSON API

curl "https://interslavic.valksor.com/api/search?query=slovo"
curl "https://interslavic.valksor.com/api/search?query=word&search_language=eng"
curl "https://interslavic.valksor.com/api/inflections?entry_id=33555&word_class=noun"

Interactive docs: /api/docs · OpenAPI schema: /api/openapi.json · LLM usage: /llms.txt

How lookup works

Any form of a word works as a query — an inflected form is resolved to its headword via the bundled reverse form index, and the result says which way it was found (search_method = direct · lemma_index · translations). Both scripts work for headwords (Latin and Cyrillic), and diacritics are optional — delati finds dělati. English→Interslavic works too: with search_language=eng the query is an English word and its Interslavic equivalents come from the dictionary's English glosses. Because Interslavic is fully regular, the inflection tables are generated by the official Interslavic morphology engine at build time — real forms, not attested citations (there is no attested Interslavic corpus). Only isv and eng are queryable; the other 11 languages are read-only columns in each entry's matrix.