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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so the safety profile is covered. The description adds genuine context by disclosing the exact formula and that both volume and area are returned, confirming this is a pure deterministic computation with no side effects.

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?

Front-loaded with the core computation and formula, then use case, inputs, and returns in tight sentences. Slightly redundant to restate 'Returns volume and area' when an output schema already documents that, costing it the top mark.

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 two-parameter pure calculator with a full output schema and complete annotations, the description supplies everything needed: what it computes, the formula, when to use it, and the input meaning. Nothing required for correct invocation 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% (both radii are documented), so the baseline is 3. The description restates 'major radius R, minor radius r' and shows them in the formula V=2π²Rr², which adds marginal meaning but nothing beyond 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?

States a specific verb and resource ('Compute torus volume ... and surface area') and even gives the exact formula, which distinguishes it immediately from the many geometry siblings (calculate_sphere, calculate_cone, calculate_cylinder, calculate_volume). An agent can select it without opening the schema.

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?

Provides concrete usage context ('Use for ring-shaped objects (donuts, inner tubes)') and cross-references list_bundles for related math calculators. It lacks explicit when-not-to-use guidance versus other 3D-shape calculators, so it falls short of a 5.

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