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

Annotations already declare read-only, idempotent, non-destructive and closed-world, so the safety profile needs no restating. The description usefully adds which loss factors are modeled and what is returned ('required wattage and common panel configurations'), but says nothing about assumptions, edge cases, or limits on inputs.

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?

Three sentences, front-loaded with the purpose, then method, then return value. No filler, though the parenthetical loss list partially duplicates the systemEfficiency schema description.

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?

No output schema exists, and the description compensates by naming the two return values. For a simple, fully annotated, single-purpose calculator with fully documented parameters, little an agent needs 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?

Schema description coverage is 100% and every parameter is documented with units, defaults and example ranges, so the schema does the heavy lifting. The description only mentions efficiency losses conceptually and adds no syntax or format detail beyond the schema — baseline 3.

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 and resource ('calculate the required solar panel wattage to cover daily energy consumption') and names the inputs it accounts for. The resource is clearly distinct from the battery/inverter/wire siblings, though it never names an alternative explicitly.

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?

Usage is implied by 'to cover daily energy consumption', which ties it to the power-budget workflow, but there is no explicit when-to-use or when-not, and no stated prerequisites (e.g. that consumption should come from calculate_power_budget first).

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