Medium Risk

create_projection

create_projection

How to control create_projection ↓

What create_projection does on KurrentDB MCP Server

AI agents use create_projection to create or update resources in KurrentDB MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your KurrentDB MCP Server environment.

Medium Risk

Why create_projection needs a policy

This tool creates a projection in KurrentDB, which is a reversible write operation. It modifies the system state by adding a new projection but does not irreversibly delete data (thus not Destructive) or execute arbitrary code (thus not Execute). The empty tool description lowers confidence slightly, but the server context and tool name are clear.

From the tool's definition Tool name 'create_projection' and server description stating 'create, test, and debug projections on KurrentDB'. The word 'create' indicates data creation/modification.

Documented attack patterns abuse exactly the kind of access create_projection gives an agent:

How to control create_projection

PolicyLayer is an MCP gateway — it sits between your AI agents and KurrentDB MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for create_projection:

policy.json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "create_projection": {
      "limits": [
        {
          "counter": "create_projection_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

create_projection 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.

  1. Create a free account and register KurrentDB MCP Server — nothing to install.
  2. Add this policy — paste it, or build it visually.
  3. Point your MCP client (Claude, Cursor, anything) at your gateway URL.
LIMIT THIS TOOL →

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Related tools and policies

Go deeper

Questions about create_projection

What does the create_projection tool do? +

create_projection. It is categorised as a Write tool in the KurrentDB MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on create_projection? +

Register the KurrentDB MCP Server MCP server in PolicyLayer and add a rule for create_projection: 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 KurrentDB MCP Server. Nothing to install.

What risk level is create_projection? +

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

Can I rate-limit create_projection? +

Yes. Add a rate_limit block to the create_projection 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 create_projection completely? +

Set action: deny in the PolicyLayer policy for create_projection. 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 create_projection? +

create_projection is provided by the KurrentDB MCP Server MCP server (kurrent-io/mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every KurrentDB MCP Server tool call.

Start from KurrentDB MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

Free to start. No card required.

8 KurrentDB MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.

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