jpl_jd_calConvert between Julian dates and UTC calendar dates with NASA's JPL JD-Calendar API, enabling date conversion for astronomy and space data.
Convert between Julian dates and calendar dates (UTC) with the JPL JD-Calendar API.
| Name | Required | Description | Default |
|---|---|---|---|
| cd | No | Calendar date (UTC) to convert to a Julian date. | |
| jd | No | Julian date to convert to a calendar date. |
Changes observed during successful MCP inspections.
v1.2.0Input schema / additionalPropertiesAdded value: +falseInput schema / properties / cd / descriptionPrevious value: -"Calendar date to convert to Julian date (YYYY-MM-DD or YYYY-MM-DDThh:mm:ss format)"New value: +"Calendar date (UTC) to convert to a Julian date."Input schema / properties / cd / patternAdded value: +"^-?\\d{1,4}-\\d{2}-\\d{2}([T_ ]\\d{2}:\\d{2}(:\\d{2}(\\.\\d+)?)?)?$"Input schema / properties / jd / descriptionPrevious value: -"Julian date to convert to calendar date"New value: +"Julian date to convert to a calendar date."Input schema / properties / jd / patternAdded value: +"^-?\\d+(\\.\\d+)?$"Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=true and destructiveHint=false, so the safety profile is fully covered. The description only adds the '(UTC)' timezone and API name, but says nothing about return format, error behavior, or whether both params may be sent simultaneously.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
A single front-loaded sentence that states verb, resource, timezone, and API with zero filler. Nothing can be trimmed without losing information.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a simple two-param converter with full schema coverage and no output schema, the description is close to adequate. However it omits the interaction rule between the two optional parameters, which an agent needs in order to invoke the tool correctly.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%, so both parameters are already documented by the schema patterns and descriptions. The description adds no syntax, format, or mutual-exclusivity detail beyond what the schema provides, so the baseline 3 applies.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
States a specific verb ('Convert between') and specific resources ('Julian dates and calendar dates (UTC)'), and names the backing API. This is unambiguous and no sibling tool overlaps the date-conversion domain, so differentiation is implicitly satisfied.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description gives no when-to-use context and, critically, no guidance on which parameter to supply. Since both 'cd' and 'jd' are optional and non-required, an agent gets no help deciding whether to provide one or both, or what happens with neither.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.