Bring Llm Tracing
to LangChain
Learn how to connect Langfuse (LLM Tracing & Evals) to LangChain and start using 10 AI agent tools in minutes. Fully managed, enterprise secure, and ready to use without writing a single line of code.
GDPR Free for Subscribers
What is the Langfuse (LLM Tracing & Evals) MCP Server?
Connect your Langfuse account to any AI agent and take full control of your LLM observability, prompt management, and quality evaluation through natural conversation.
What you can do
- Trace Orchestration — List and retrieve detailed traces of LLM API sessions, exposing latencies, token counts, and exact chained payloads directly from your agent
- Prompt Vault Access — Query actively managed prompt templates and versions to inspect system instructions and expected input variables
- Observation Analysis — Deep-dive into individual spans, events, and generations within a trace to pinpoint failures or performance bottlenecks securely
- Evaluation & Scoring — Attach structured human feedback or automated evaluation metrics to specific traces to monitor model grounding and accuracy
- Usage Metrics — Generate aggregated daily reports on USD costs and average latency to track your AI infrastructure spending in real-time
- Session Monitoring — Extract correlated user sessions to understand multi-turn interaction boundaries and improve long-term agentic workflows
How it works
1. Subscribe to this server
2. Enter your Langfuse API URL, Public Key, and Secret Key
3. Start monitoring your LLM application from Claude, Cursor, or any MCP-compatible client
Who is this for?
- LLM Engineers — debug complex AI chains and measure exact token latencies through natural conversation without manual dashboard searching
- Product Owners — monitor daily AI costs and user satisfaction scores across multiple production environments
- Data Scientists — manage prompt templates and audit evaluation metrics to improve model response quality and grounding efficiently
Built-in capabilities (10)
Create a new LLM observation (span, event, generation) inside a trace
g. 1-5 stars) or automated pipeline metrics bounding exactly onto the specified Trace or Observation. Attach human feedback or evaluation metrics to a trace/observation
Generate rolled-up USD cost and aggregated latency statistics
Retrieve explicit span or generation context within a trace
Get complete telemetry and nested graph for a single trace
List raw observation objects spanning across traces
Extract actively managed prompt templates and versions
List all explicit scores mapping quality or cost algorithms
List high-level user session entities encapsulating multiple traces
List all traces tracking LLM API sessions
Why LangChain?
LangChain's ecosystem of 500+ components combines seamlessly with Langfuse (LLM Tracing & Evals) through native MCP adapters. Connect 10 tools via Vinkius and use ReAct agents, Plan-and-Execute strategies, or custom agent architectures. with LangSmith tracing giving full visibility into every tool call, latency, and token cost.
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The largest ecosystem of integrations, chains, and agents. combine Langfuse (LLM Tracing & Evals) MCP tools with 500+ LangChain components
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Agent architecture supports ReAct, Plan-and-Execute, and custom strategies with full MCP tool access at every step
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LangSmith tracing gives you complete visibility into tool calls, latencies, and token usage for production debugging
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Memory and conversation persistence let agents maintain context across Langfuse (LLM Tracing & Evals) queries for multi-turn workflows
Langfuse (LLM Tracing & Evals) in LangChain
Langfuse (LLM Tracing & Evals) and 3,400+ other MCP servers. One platform. One governance layer.
Teams that connect Langfuse (LLM Tracing & Evals) to LangChain through Vinkius don't need to source, host, or maintain individual MCP servers. Every tool call runs inside a hardened runtime with credential isolation, DLP, and a signed audit chain.
Raw MCP | Vinkius | |
|---|---|---|
| Server catalog | Find and host yourself | 3,400+ managed |
| Infrastructure | Self-hosted | Sandboxed V8 isolates |
| Credential handling | Plaintext in config | Vault + runtime injection |
| Data loss prevention | None | Configurable DLP policies |
| Kill switch | None | Global instant shutdown |
| Financial circuit breakers | None | Per-server limits + alerts |
| Audit trail | None | Ed25519 signed logs |
| SIEM log streaming | None | Splunk, Datadog, Webhook |
| Honeytokens | None | Canary alerts on leak |
| Custom domains | Not applicable | DNS challenge verified |
| GDPR compliance | Manual effort | Automated purge + export |
Why teams choose Vinkius for Langfuse (LLM Tracing & Evals) in LangChain
The Langfuse (LLM Tracing & Evals) MCP Server runs on Vinkius-managed infrastructure inside AWS — a purpose-built runtime with per-request V8 isolates, Ed25519 signed audit chains, and sub-40ms cold starts. All 10 tools execute in hardened sandboxes optimized for native MCP execution.
Your AI agents in LangChain only access the data you authorize, with DLP that blocks sensitive information from ever reaching the model, kill switch for instant shutdown, and up to 60% token savings. Enterprise-grade infrastructure, zero maintenance.
* Every MCP server runs on Vinkius-managed infrastructure inside AWS - a purpose-built runtime with per-request V8 isolates, Ed25519 signed audit chains, and sub-40ms cold starts optimized for native MCP execution. See our infrastructure
How Vinkius secures
Langfuse (LLM Tracing & Evals) for LangChain
Every tool call from LangChain to the Langfuse (LLM Tracing & Evals) MCP Server is protected by DLP redaction, cryptographic audit chains, V8 sandbox isolation, kill switch, and financial circuit breakers.
Frequently asked questions
Can I see the exact system instruction for a specific prompt version?
Yes. Use the list_prompts tool to browse your managed templates. Your agent can retrieve the exact text and variables for any deployed prompt version, making it easy to audit AI logic through natural conversation.
How do I log human feedback for a specific trace?
Use the create_score tool by providing the Trace ID and a JSON payload defining the score name (e.g. 'user-satisfaction') and value. Your agent will attach this structured data directly to the Langfuse record.
Can my agent report on my LLM spending for the current day?
Absolutely. The get_daily_metrics tool retrieves aggregated USD costs and average latency metrics from Langfuse. Your agent can summarize these statistics to help you monitor your infrastructure budget in real-time.
How does LangChain connect to MCP servers?
Use langchain-mcp-adapters to create an MCP client. LangChain discovers all tools and wraps them as native LangChain tools compatible with any agent type.
Which LangChain agent types work with MCP?
All agent types including ReAct, OpenAI Functions, and custom agents work with MCP tools. The tools appear as standard LangChain tools after the adapter wraps them.
Can I trace MCP tool calls in LangSmith?
Yes. All MCP tool invocations appear as traced steps in LangSmith, showing input parameters, response payloads, latency, and token usage.
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Install: pip install langchain-mcp-adapters