NASA InSight Mars weather (historical)

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

Annotations already cover readOnly/idempotent/destructive/openWorld, but the description adds genuinely non-structured context: the feed is permanently frozen at a specific sol range and requires NASA_API_KEY. Data staleness and auth requirements are exactly what an agent needs to know and cannot infer from annotations.

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?

Two tight sentences with the most important constraint (HISTORICAL DATA ONLY) front-loaded. Every clause earns its place: scope, fields, staleness, sol range, auth.

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 no-parameter, no-output-schema tool, the description covers what it returns (temperature, pressure, wind), where it comes from, why it's static, and what's required to call it. Nothing material is missing.

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?

Zero parameters, so there is nothing to document and the baseline is 4. The description appropriately spends its words on scope and freshness rather than inventing parameter guidance.

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/resource (per-sol Mars surface weather) plus the data source and location (InSight lander, Elysium Planitia). The 'HISTORICAL DATA ONLY' framing immediately distinguishes it from a live-weather tool.

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?

Makes clear when this is appropriate (historical/archival use) and warns that the feed is frozen at sols 675-681 and no longer updated, which is a strong usage signal. It stops short of naming an alternative sibling (e.g., nasa_mars_rover) for current conditions, so it isn't a full when/when-not routing.

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