estimate_data_size

THE RISK

Low Risk

Why estimate_data_size needs a policy

This tool retrieves or computes information (an estimate) about a hypothetical dataset without side effects. It does not create, modify, delete, or execute external operations. It is a query helper that returns informational output. Estimation operations on geospatial metadata are read-only and pose minimal risk even if an AI agent misuses the parameters.

From the tool's definition Tool name is 'estimate_data_size' and description states it 'Estimate[s] the data size for a STAC query.' The verb 'estimate' indicates a read-only operation that computes metadata about potential query results without retrieving, modifying, deleting, or…

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

POLICY

How to control estimate_data_size

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

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "estimate_data_size": {}
  }
}

estimate_data_size is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.

Create a free account and register STAC 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.

CAP THIS TOOL →

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EXPLORE

Related tools and policies

More STAC MCP Server tools

Read get_aggregations Get aggregations for STAC items. Read get_collection Fetch a single STAC Collection by id. Read get_conformance Return server conformance classes. Read get_item Get a specific STAC Item by collection and item ID. Read get_queryables Get the queryable properties for a specific STAC collection by its ID. Read get_root Return the STAC root document for a catalog. Read get_sensor_registry_info Get information about the STAC sensor registry. Read search_collections Return a page of STAC collections.

All 10 STAC MCP Server tools →

Read 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.
Data exfiltration → How read access becomes an exfiltration channel when chained with untrusted content.
MCP token cost → What connecting this server costs in context-window tokens on every request.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about estimate_data_size

What does the estimate_data_size tool do? +

Estimate the data size for a STAC query. It is categorised as a Read tool in the STAC MCP Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on estimate_data_size? +

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

What risk level is estimate_data_size? +

estimate_data_size is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit estimate_data_size? +

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

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

estimate_data_size is provided by the STAC MCP Server MCP server (wayfinder-foundry/stac-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every STAC MCP Server tool call.

Start from STAC 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 →