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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safe, side-effect-free nature is covered. The description adds real behavioral value by giving the exact formula, which tells the agent the computation is deterministic and how inputs combine. It omits rounding behavior for the sheet count.

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 short sentences: the purpose is front-loaded and the formula follows immediately, with no filler or restated name.

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 stateless calculator with full schema coverage and no output schema, the description supplies purpose plus computation logic. The main remaining gap is whether the returned sheet count is rounded up and what units it is in, which an agent might need to interpret the result.

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%, so 3 is the baseline. The formula goes beyond field-level definitions by showing how wall_perimeter_ft, wall_height_ft, ceiling dimensions, waste_pct, and sheet dimensions interact, which adds genuine meaning over the schema.

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 states a specific resource and output unit (number of drywall sheets for walls plus optional ceiling), which clearly separates it from the other calc_* siblings such as calc_paint or calc_insulation_r_value. It does not explicitly name an alternative, but the resource is unambiguous.

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 the phrasing 'for walls and optionally the ceiling,' which signals the include_ceiling toggle, but there is no explicit when-to-use vs. when-not guidance and no alternative tool named. Adequate but not directive.

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