AI agents use add_marker to create or update resources in Metashape MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Metashape MCP Server environment.
This tool creates a new marker object in the photogrammetry project, modifying the project state reversibly. It is a Write action since markers can be added and removed. While it affects project data, the blast radius is contained to marker metadata rather than core 3D model geometry or exports.
From the tool's definition Tool description states it will 'Add a marker manually to the active chunk', which creates new data in the Metashape project.
Documented attack patterns abuse exactly the kind of access add_marker gives an agent:
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 add_marker:
{
"version": "1",
"default": "deny",
"tools": {
"add_marker": {
"limits": [
{
"counter": "add_marker_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}add_marker 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.
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Add a marker manually to the active chunk. 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.
Register the Metashape MCP Server MCP server in PolicyLayer and add a rule for add_marker: 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.
add_marker is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the add_marker 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.
Set action: deny in the PolicyLayer policy for add_marker. 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.
add_marker 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.
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.
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112 Metashape MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.