get_planet

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds meaningful behavioral context beyond that: it states the data source ('Planetary Systems Composite Parameters table') and the best-available nature of values, plus the distinction that only confirmed exoplanets are included. It does not contradict annotations, and the extra context about data provenance is valuable.

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 structured in three focused paragraphs: purpose and return categories, usage guidance and naming constraints, and data source. Each sentence earns its place, no fluff. It is front-loaded with the core purpose, and the additional details are directly useful.

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?

With a single parameter, full schema coverage, rich annotations, and an output schema, the description adds complementary context: usage after search, exact name handling, and the composite data table. It covers all necessary aspects for an agent to select and invoke this tool correctly, without needing to explain return values since the output schema exists.

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 coverage is 100%: the input schema fully describes planet_name with exact spelling, case-sensitivity, and guidance to use resolve_name. The description repeats these details (e.g., 'must be exact,' 'Kepler-22 b, not Kepler-22b') without adding new meaning beyond what the schema already provides. Baseline 3 is appropriate when the schema does the heavy lifting.

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 uses a specific verb ('Get') and resource ('comprehensive details for a single confirmed exoplanet by exact name'), clearly distinguishing it from siblings like search_planets (which searches) and resolve_name (which canonicalizes names). It explicitly frames this tool as the follow-up to search_planets for full details on a single result, making its purpose unmistakable.

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 explicit when-to-use guidance: 'Use this after search_planets to get full details on a specific result, or when the user asks about a specific known planet.' It also provides a clear alternative: 'If unsure of the exact name, use resolve_name first.' This is excellent contextual guidance that names the alternative tool and the condition for choosing it.

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