AI agents invoke geometry-union to trigger actions in PostGIS MCP Server. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.
A geometry union operation computes a new geometry from multiple inputs. It is a spatial computation/transformation that runs a database operation (ST_Union or similar). It doesn't purely read existing data nor does it write/persist results by itself based on description alone, placing it in Execute.
From the tool's definition 'Birden fazla geometriyi birleştir' (Merge/union multiple geometries) - performs a spatial union operation on geometries
Documented attack patterns abuse exactly the kind of access geometry-union gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and PostGIS MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for geometry-union:
{
"version": "1",
"default": "deny",
"tools": {
"geometry-union": {
"limits": [
{
"counter": "geometry-union_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}geometry-union stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
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Birden fazla geometriyi birleştir. It is categorised as a Execute tool in the PostGIS MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the PostGIS MCP Server MCP server in PolicyLayer and add a rule for geometry-union: 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 PostGIS MCP Server. Nothing to install.
geometry-union is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the geometry-union 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 geometry-union. 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.
geometry-union is provided by the PostGIS MCP Server MCP server (receptopalak/postgis-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from PostGIS 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.
25 PostGIS MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.