jpl_horizons

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries full burden for behavioral disclosure. It mentions 'ephemeris data', implying a read-only query, but doesn't specify rate limits, authentication needs, data freshness, or error handling. For a tool with 11 parameters and no output schema, this lack of operational context is a significant gap.

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?

The description is extremely concise—a single phrase that efficiently conveys the core function. It's front-loaded with no wasted words, making it easy to parse. This is appropriate given the detailed schema, though it may be too brief for full context.

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?

Given the complexity (11 parameters, no annotations, no output schema), the description is incomplete. It doesn't explain what ephemeris data includes, how results are structured, or typical use cases. While the schema covers inputs, the lack of output details and behavioral context makes this inadequate for a tool of this sophistication.

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 parameters are well-documented in the schema itself. The description adds no additional parameter semantics beyond implying ephemeris generation. This meets the baseline of 3, as the schema does the heavy lifting, but the description doesn't compensate with examples or clarification of complex parameters like 'CENTER' or 'QUANTITIES'.

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?

The description clearly states the tool's purpose: 'JPL Horizons - Solar system objects ephemeris data'. It specifies the verb (providing ephemeris data) and resource (solar system objects), making it understandable. However, it doesn't differentiate from siblings like 'jpl_horizons_file' or 'jpl_sbdb', which likely serve related but distinct purposes in the JPL ecosystem.

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 provides no guidance on when to use this tool versus alternatives. With many sibling tools (e.g., 'jpl_cad', 'jpl_sbdb', 'nasa_neo'), there's no indication of context, prerequisites, or exclusions. This leaves the agent to guess based on tool names alone, which is insufficient for effective selection.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.