Nearest neighbor spatial join using geopandas.sjoin_nearest. Args: left_path: Path to the left geospatial file. right_path: Path to the right geospatial file. how: Type of join ('left', 'right'). max_distance: Optional maximum search distance. output_path: Optional path to save the result. Return...
AI agents use sjoin_nearest_gpd to create or update resources in GIS MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your GIS MCP Server environment.
The tool performs a nearest neighbor spatial join between two geospatial datasets and can write the output to a file. The core operation is a read/compute (spatial join), but the optional save to output_path makes it a Write operation. It does not execute arbitrary code, delete data, or involve financial transactions.
From the tool's definition 'output_path: Optional path to save the result' and 'Returns: Dictionary with status, message, and output info' — the tool performs a spatial join and optionally writes the result to disk
Documented attack patterns abuse exactly the kind of access sjoin_nearest_gpd gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and GIS MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for sjoin_nearest_gpd:
{
"version": "1",
"default": "deny",
"tools": {
"sjoin_nearest_gpd": {
"limits": [
{
"counter": "sjoin_nearest_gpd_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}sjoin_nearest_gpd 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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Nearest neighbor spatial join using geopandas.sjoin_nearest. Args: left_path: Path to the left geospatial file. right_path: Path to the right geospatial file. how: Type of join ('left', 'right'). max_distance: Optional maximum search distance. output_path: Optional path to save the result. Returns: Dictionary with status, message, and output info. It is categorised as a Write tool in the GIS MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the GIS MCP Server MCP server in PolicyLayer and add a rule for sjoin_nearest_gpd: 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 GIS MCP Server. Nothing to install.
sjoin_nearest_gpd 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 sjoin_nearest_gpd 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 sjoin_nearest_gpd. 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.
sjoin_nearest_gpd is provided by the GIS MCP Server MCP server (mahdin75/gis-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from GIS 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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98 GIS MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.