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

Annotations already declare readOnly/idempotent/non-destructive, so safety is covered. The description instead makes behavioral claims about its inputs ('latitude, panel orientation, shading %') that are factually wrong for this tool, which is more harmful than silence – it misleads the agent about what the tool actually computes.

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 text is short and front-loads the purpose and use case, which is good structure. However, one of its four sentences is an inaccurate input inventory, so not every sentence earns its place.

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 values need not be explained, but the description still leaves critical gaps: no mention of how location/orientation are handled despite claiming 'by location', no relationship to calculate_solar_roi, and a parameter list that does not match the actual schema.

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%, which normally sets a baseline of 3, but the description's input list contradicts the schema: latitude, panel orientation and shading % do not exist, while the real parameters (panel_watt_peak, hours_sun_per_day, efficiency_loss_pct, area_m2) are never named. The description therefore subtracts value rather than adding it.

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 ('Estimate solar panel daily and yearly energy output') and even gives the use case (solar installation sizing), so an agent can identify the tool. It does not, however, distinguish itself from the sibling calculate_solar_roi, which is the most likely confusion in this catalog.

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 for solar installation sizing' gives an implied context and the pointer to list_bundles for related 'energie' calculators is a useful routing hint. There is no explicit when-not-to-use or comparison against calculate_solar_roi, so the agent must infer the boundary between output estimation and ROI.

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