AI agents call jpl_horizons_file to retrieve information from Nasa without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries historical and predictive positional data about celestial bodies from NASA JPL's Horizons system. File input is used to specify query parameters (object identifiers, time ranges, etc.), but the operation itself only retrieves and returns data without side effects, modifications, or execution of arbitrary code.
From the tool's definition Retrieves ephemeris data for solar system objects. The description indicates data retrieval (ephemeris data) with file input, which is a read operation that queries JPL Horizons database without modifying or executing arbitrary operations.
Attacks that exploit this kind of access
JPL Horizons - Solar system objects ephemeris data (File Input). It is categorised as a Read tool in the Nasa MCP Server, which means it retrieves data without modifying state.
Register the Nasa MCP server in PolicyLayer and add a rule for jpl_horizons_file: 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 Nasa. Nothing to install.
jpl_horizons_file is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the jpl_horizons_file 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 jpl_horizons_file. 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.
jpl_horizons_file is provided by the Nasa MCP server (@programcomputer/nasa-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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