set_active_tree · Tiling Trees MCP Server MCP: Risk & Policy

WHAT IT DOES

What set_active_tree does on Tiling Trees MCP Server

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

WHY IT NEEDS A POLICY

Why set_active_tree needs a policy

This tool creates or modifies state (the active tree context) in a way that affects how subsequent tools behave. It does not permanently delete data (would be Destructive), does not retrieve data without side effects (would be Read), does not execute arbitrary code (would be Execute), and does not involve financial transactions (would be Financial).

From the tool's definition The tool 'set_active_tree' modifies the active context state by setting which tree is currently active, as indicated by 'Once set, tools with optional treeId default to this tree'. This changes application state in a reversible manner.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

set_active_tree Rate-limited

set_active_tree 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": {
    "set_active_tree": {
      "limits": [
        {
          "counter": "set_active_tree_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 Tiling Trees MCP Server, so you can run agents against it safely.

FAQ

Questions about set_active_tree

What does the set_active_tree tool do? +

Set the active tree context. Once set, tools with optional treeId default to this tree, and path-based tile lookup is enabled (e.g.,. It is categorised as a Write tool in the Tiling Trees 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 set_active_tree? +

Register the Tiling Trees MCP Server MCP server in PolicyLayer and add a rule for set_active_tree: 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 Tiling Trees MCP Server. Nothing to install.

What risk level is set_active_tree? +

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

Can I rate-limit set_active_tree? +

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

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

set_active_tree is provided by the Tiling Trees MCP Server MCP server (k-chrispens/tiling-trees-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.