createScore · Langfuse Mcp Extended MCP: Risk & Policy

WHAT IT DOES

What createScore does on Langfuse Mcp Extended

AI agents use createScore to create or update resources in Langfuse Mcp Extended — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Langfuse Mcp Extended environment.

WHY IT NEEDS A POLICY

Why createScore needs a policy

This tool creates (Write operation) scoring data associated with traces or observations in Langfuse. It modifies state by adding a new score record but is reversible - scores can be updated or deleted via other tools on the server (deleteScore exists). The impact is contained to scoring metadata rather than core data deletion.

From the tool's definition Tool name is 'createScore' with description stating 'Create a score' - explicit Create operation that adds new data to a trace/observation record without irreversible deletion.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

createScore Rate-limited

createScore stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "createScore": {
      "limits": [
        {
          "counter": "createscore_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Langfuse Mcp Extended, so you can run agents against it safely.

FAQ

Questions about createScore

What does the createScore tool do? +

Create a score for a trace or observation. Supports numeric, boolean, and categorical score types. It is categorised as a Write tool in the Langfuse Mcp Extended MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on createScore? +

Register the Langfuse Mcp Extended MCP server in PolicyLayer and add a rule for createScore: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Langfuse Mcp Extended. Nothing to install.

What risk level is createScore? +

createScore is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit createScore? +

Yes. Add a rate_limit block to the createScore rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block createScore completely? +

Set action: deny in the PolicyLayer policy for createScore. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides createScore? +

createScore is provided by the Langfuse Mcp Extended MCP server (langfuse-mcp-extended). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.