Langfuse MCP Java vs Spanlens

In-depth architectural comparison of the Langfuse MCP Java and Spanlens MCP servers. Compare execution transports, security boundaries, tool capabilities, quality scores, and ready-to-paste client installation snippets for Claude, Cursor, Windsurf, and VS Code.

Which MCP Server Should You Choose?

Choose Langfuse MCP Java when:

• You need dedicated capabilities in the Monitoring domain.
• You prefer remote streaming HTTP/SSE transport architecture.
• Your security boundary fits: API Key required (BYOK (Pay Provider Direct)).
• You have access to required keys: LANGFUSE_PUBLIC_KEY, LANGFUSE_SECRET_KEY, LANGFUSE_HOST, LANGFUSE_TIMEOUT.
• Primary tools included: fetch_traces, fetch_trace, find_exceptions.

Explore Langfuse MCP Java Details

Choose Spanlens when:

• You need dedicated capabilities in the Monitoring domain.
• You prefer local stdio subprocess transport architecture.
• Your security boundary fits: API Key required (Free / Open Source).
• You have access to required keys: SPANLENS_API_KEY.
• Primary tools included: .

Feature & Specification Comparison

Specification	Langfuse MCP Java log-logn Monitoring	Spanlens spanlens Monitoring
Summary	Query Langfuse traces, debug exceptions, analyze sessions, scores, datasets, schema, observations and manage prompts. Full observability toolkit for LLM applications. (https://github.com/langfuse/langfuse)	Query your Spanlens LLM observability from any MCP client. 7 read tools for request logs, agent traces, cost stats, anomalies, model-savings, and per-user analytics across OpenAI, Anthropic, and Gemini. Open source, self-hostable. npx -y @spanlens/mcp-server
Category & Scope

Tools & Capabilities Breakdown

Ready-to-Paste Client Configurations

Paste either (or both) of these JSON server blocks into your client config file (e.g. claude_desktop_config.json or ~/.cursor/mcp.json).

{
  "mcpServers": {
    "log-logn-langfuse-mcp-java": {
      "url": "http://localhost:8080/mcp"
    }
  }
}

{
  "mcpServers": {
    "spanlens-spanlens-2": {
      "command": "npx",
      "args": [
        "-y",
        "@spanlens/cli"
      ],
      "env": {
        "SPANLENS_API_KEY": "YOUR_SPANLENS_API_KEY_HERE"
      }
    }
  }
}

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