AI agents call jpl_jd_cal 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 pure computational tool that converts between two date/time formats. It retrieves or computes information based on input parameters without creating, modifying, deleting, or executing external operations. The conversion is deterministic and reversible, with no persistent state changes or external system impacts. Therefore, it qualifies as a Read operation with low risk.
From the tool's definition Tool performs bidirectional conversion between Julian Day numbers and calendar dates/times. The description explicitly indicates this is a data conversion/transformation utility with no side effects.
Attacks that exploit this kind of access
Julian Day number to/from calendar date/time converter. 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_jd_cal: 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_jd_cal 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_jd_cal 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_jd_cal. 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_jd_cal 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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