AI agents call jpl_horizons 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 is a read-only data retrieval tool that queries NASA's Horizons system for astronomical ephemeris data. No side effects, modifications, code execution, or data destruction are possible. Misuse would at worst return incorrect positional data for celestial objects, which has no direct impact on systems or assets.
From the tool's definition Tool retrieves 'ephemeris data' (positional and orbital information) for solar system objects from JPL Horizons. The description uses a query/retrieval verb ('data') with no write, execute, or delete capability indicated.
Attacks that exploit this kind of access
JPL Horizons - Solar system objects ephemeris data. 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: 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 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 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. 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 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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