LangSearch MCP Server

MCP server for LangSearch Web Search & Semantic Rerank API.

Features

• Web Search: Search the web with titles, URLs, snippets, summaries, and freshness filters
• Semantic Rerank: Reorder documents by relevance using neural reranker
• Dual Output: Markdown (human-readable) and JSON (machine-readable)

Installation

Option 1: npx (recommended)

No install needed — just configure Claude Code or Claude Desktop:

{
  "mcpServers": {
    "langsearch": {
      "command": "npx",
      "args": ["-y", "langsearch-mcp-server"],
      "env": {
        "LANGSEARCH_API_KEY": "sk-your-key"
      }
    }
  }
}

Restart your client after saving.

Option 2: Local Install

npm install -g langsearch-mcp-server
export LANGSEARCH_API_KEY="sk-your-key"

Then configure:

{
  "mcpServers": {
    "langsearch": {
      "command": "langsearch-mcp-server",
      "env": {
        "LANGSEARCH_API_KEY": "sk-your-key"
      }
    }
  }
}

Option 3: Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "langsearch": {
      "command": "npx",
      "args": ["-y", "langsearch-mcp-server"],
      "env": {
        "LANGSEARCH_API_KEY": "sk-your-key"
      }
    }
  }
}

Restart Claude Desktop after saving.

Option 4: From Source

git clone https://github.com/fusman60/langsearch-mcp-server.git
cd mcp-server
npm install
export LANGSEARCH_API_KEY="sk-your-key"

Configure with:

{
  "mcpServers": {
    "langsearch": {
      "command": "node",
      "args": ["/absolute/path/to/langsearch-mcp-server/src/index.js"],
      "env": {
        "LANGSEARCH_API_KEY": "sk-your-key"
      }
    }
  }
}

Tools

langsearch_web_search

Search the web using LangSearch API.

Parameters: | Parameter | Type | Required | Default | Description | |-----------|------|----------|---------|-------------| | query | string | Yes | - | Search query (1-500 chars) | | count | number | No | 10 | Results to return (1-10) | | freshness | enum | No | noLimit | oneDay, oneWeek, oneMonth, oneYear, noLimit | | summary | boolean | No | false | Include detailed text summaries | | response_format | enum | No | markdown | 'markdown' or 'json' |

Example:

Search for "Claude Code AI assistant" with freshness=oneWeek

langsearch_semantic_rerank

Reorder documents by semantic relevance to a query.

Parameters: | Parameter | Type | Required | Default | Description | |-----------|------|----------|---------|-------------| | query | string | Yes | - | Query to rank against | | documents | string[] | Yes | - | Array of document texts (1-100) | | top_n | number | No | - | Return only top N results (1-100) | | response_format | enum | No | markdown | 'markdown' or 'json' |

Example:

Rerank 10 search results for "transformer attention mechanisms"

API Reference

• API Base: https://api.langsearch.com
• Web Search Endpoint: POST /v1/web-search
• Rerank Endpoint: POST /v1/rerank
• Dashboard: https://langsearch.com/dashboard

License

MIT