Bareun — Korean NLP & Spell/Grammar Checking

License: MIT

바른(Bareun) is a Korean natural-language platform. This is its MCP (Model Context Protocol) server — it lets any MCP-compatible AI tool (Claude, Cursor, VS Code, Claude Desktop, …) perform Korean morphological analysis and spell/grammar correction by calling Bareun as a tool.

Large language models still miss the subtle spacing, particle agreement, and confusable-word rules of Korean. Plug Bareun in as an MCP tool and your agent can hand off analysis and proofreading to a dedicated Korean engine, then use the result to produce more accurate Korean output.

• Hosted endpoint: https://api.bareun.ai/mcp
• Transport: Streamable HTTP (JSON-RPC 2.0) — no SSE, no extra port, no install
• Auth: API key (api-key header or Authorization: Bearer <key>)
• Get an API key: https://bareun.ai

The /mcp endpoint is available on the spell-checker–included build of Bareun (the morphological-analysis-only build does not expose /mcp). The same endpoint works on self-hosted/on-prem installs — just swap the host.

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Tools

Tool	What it does	Key inputs
analyze_syntax	Splits a sentence into words/morphemes and tags parts of speech (morphological analysis).	text (required), auto_split_sentence, auto_spacing, auto_jointing, custom_dict_names, encoding, format (full|compact)
tokenize	Splits a sentence into word (token) units.	text (required), auto_spacing, encoding
correct_grammar	Corrects spelling/spacing and returns correction blocks.	text (required), custom_dict_names, + 9 boolean correction options
list_pos_tags	Returns the 47 part-of-speech tags Bareun uses (code · name · class).	(none)

correct_grammar options (all boolean, default off): treat_as_title, disable_split_sentence, disable_caret_spacing, disable_vx_spacing, enable_limited_punctuation, disable_confusion, enable_cleanup_whitespace, disable_typo_correction, enable_sentence_check.

encoding controls the unit for morpheme offsets: utf32 (default, code points — matches Python), utf16 (JS/Java), utf8 (bytes — Go/C++).

Resources

Resource URI	Contents	Auth
bareun://pos-tags	The 47 POS tags (code · name · class) — same data as list_pos_tags	API key
bareun://server-info	Server metadata — name · version · build · active tools/resources	API key
bareun://custom-dicts	Names of custom-dictionary domains registered for the key	valid API key

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Quick start

Tip — register globally. Most tools default to project scope (the server is only available in one project). To use Bareun across all your projects, register it at global / user scope as shown below.

Claude Code

# -s user → global: available in every project
claude mcp add -s user --transport http bareun https://api.bareun.ai/mcp \
  --header "api-key: YOUR_API_KEY"

Omit -s user for project-local scope. Check with claude mcp get bareun.

Cursor

Global: ~/.cursor/mcp.json · Project: <project>/.cursor/mcp.json

{
  "mcpServers": {
    "bareun": {
      "url": "https://api.bareun.ai/mcp",
      "headers": { "api-key": "YOUR_API_KEY" }
    }
  }
}

VS Code

Global: run MCP: Open User Configuration · Project: <project>/.vscode/mcp.json

{
  "servers": {
    "bareun": {
      "type": "http",
      "url": "https://api.bareun.ai/mcp",
      "headers": { "api-key": "YOUR_API_KEY" }
    }
  }
}

Claude Desktop — claude_desktop_config.json

Claude Desktop bridges header-authenticated remote servers via mcp-remote (Node.js required):

{
  "mcpServers": {
    "bareun": {
      "command": "npx",
      "args": [
        "-y", "mcp-remote",
        "https://api.bareun.ai/mcp",
        "--header", "api-key: YOUR_API_KEY"
      ]
    }
  }
}

Test with MCP Inspector

npx @modelcontextprotocol/inspector

Set Transport to Streamable HTTP, URL to https://api.bareun.ai/mcp, and add header api-key: YOUR_API_KEY.

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Example

// tools/call → analyze_syntax  (format: compact)
{ "text": "나는 학교에 간다.", "format": "compact" }
// → "나/NP 는/JX 학교/NNG 에/JKB 가/VV ㄴ다/EF ./SF"

Links

• Service: https://bareun.ai
• Docs: https://bareun.ai/docs
• MCP guide: https://bareun.ai/docs/howtouse/mcp
• API keys & usage: https://bareun.ai/docs/howtouse/cloud-api

License

The contents of this repository (documentation, registry manifests, examples) are released under the MIT License. The Bareun engine itself is a proprietary service operated by Baikal AI; access is governed by the bareun.ai terms of service.