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

With no annotations, the description carries the burden, and it does disclose the data source, the 2001-2025 long-term window, monthly aggregation, and that the PV yield figures are 'estimated' rather than measured. It says nothing about units, latency, caching, rate limits, or what happens when a location has sparse station coverage — gaps that matter for an agent interpreting results.

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 dense sentences with no filler; the source, period and outputs are front-loaded before the one usage sentence. Every clause contributes information an agent needs to make a selection.

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?

An output schema exists, so return-value detail is not required, and the description adequately frames the inputs it cares about (location, system size). However, for a 4-parameter tool with zero schema documentation, the missing parameter explanation and unit conventions leave the definition only marginally complete.

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 0% — only bare titles (Lat, Lon, System Kw, Performance Ratio). The description hints at 'for a system size', which maps loosely to system_kw, but lat/lon formats, units, and especially performance_ratio (and its 0.8 default) are left entirely undocumented, so the description does not compensate for the coverage gap.

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?

Names the exact resource (long-term monthly solar irradiance plus temperature, wind, PV yield, specific yield, capacity factor) and its provenance and window (NASA POWER, 2001-2025). The scope 'for any location on Earth' plus the derived PV metrics clearly distinguishes it from siblings like weather_forecast or sun_moon_times.

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?

'Use to screen solar sites' gives one intended use case, so usage is implied rather than spelled out. It never says when to prefer this over weather_forecast / sun_moon_times for location-based environmental data, nor any exclusions such as non-solar energy screening.

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