create_stream · S2 StreamStore MCP Server MCP: Risk & Policy

WHAT IT DOES

What create_stream does on S2 StreamStore MCP Server

AI agents use create_stream to create or update resources in S2 StreamStore MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your S2 StreamStore MCP Server environment.

WHY IT NEEDS A POLICY

Why create_stream needs a policy

This tool creates a new stream resource, which is a reversible data modification operation. It does not execute arbitrary code, delete data, or involve financial transactions. The severity is medium because creating streams could consume storage resources or alter system state, but the action is reversible (streams can be deleted via delete_stream).

From the tool's definition Tool name 'create_stream' and description 'Create a stream in a basin' indicate a creation action that modifies data state within the StreamStore system.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_stream Rate-limited

create_stream 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": {
    "create_stream": {
      "limits": [
        {
          "counter": "create_stream_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 S2 StreamStore MCP Server, so you can run agents against it safely.

FAQ

Questions about create_stream

What does the create_stream tool do? +

Create a stream in a basin. Name must be 1-512 chars. It is categorised as a Write tool in the S2 StreamStore 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_stream? +

Register the S2 StreamStore MCP Server MCP server in PolicyLayer and add a rule for create_stream: 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 S2 StreamStore MCP Server. Nothing to install.

What risk level is create_stream? +

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

Can I rate-limit create_stream? +

Yes. Add a rate_limit block to the create_stream 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_stream completely? +

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

create_stream is provided by the S2 StreamStore MCP Server MCP server (s2-streamstore/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.