Bareun MCP Server — Korean NLP & Spell/Grammar Checking
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.
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 |
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.
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
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.
