set_active_chunk

THE RISK

Medium Risk

Why set_active_chunk needs a policy

Switching an active chunk is a state-management operation that can be undone by switching back. It does not execute commands, trigger external processes, or destructively remove data. While it alters application state, the change is non-destructive and reversible, making it a Write operation.

From the tool's definition Tool description states 'Switch the active chunk' — this changes internal application state (which chunk is active) but does not delete, create new data files, or execute external operations.

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

POLICY

How to control set_active_chunk

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

policy.json

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

set_active_chunk 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.

Create a free account and register Metashape MCP Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Metashape MCP Server tools

Destructive clean_model Remove model artifacts based on filtering criteria. Destructive clear_dem Remove the DEM from the active chunk to free memory. Destructive clear_depth_maps Remove depth maps from the active chunk to free memory. Destructive clear_masks Remove masks from cameras. Destructive clear_model Remove the 3D model from the active chunk to free memory. Destructive clear_orthomosaic Remove the orthomosaic from the active chunk to free memory. Destructive clear_point_cloud Remove the dense point cloud from the active chunk to free memory. Destructive clear_tiled_model Remove the tiled model from the active chunk to free memory.

All 112 Metashape MCP Server tools →

Write tools on other servers

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Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Argument validation → Checking tool call arguments against schema and policy before they run.
Scoped token → Per-person credentials that grant a defined subset of servers and tools.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about set_active_chunk

What does the set_active_chunk tool do? +

Switch the active chunk by label or index. It is categorised as a Write tool in the Metashape 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_chunk? +

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

What risk level is set_active_chunk? +

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

Can I rate-limit set_active_chunk? +

Yes. Add a rate_limit block to the set_active_chunk 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_chunk completely? +

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

set_active_chunk is provided by the Metashape MCP Server MCP server (jenkinsm13/metashape-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Metashape MCP Server tool call.

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

CHECK YOUR STACK →