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

Annotations already declare a full safety profile (readOnly, idempotent, non-destructive, closed-world), so the description isn't required to carry that burden. It adds no behavioral context beyond structure: it doesn't mention the sides ≥ 3 constraint, custom bounded ranges, or whether the computation is exact or rounded, and 'returns full geometric properties' merely restates the output schema.

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 purpose, then inputs and routing in four short sentences. 'Returns full geometric properties' is largely redundant given the existing output schema, which is the only real slack.

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?

With a rich annotation set, a 100%-covered 2-parameter schema, and an output schema present, the description only needs to state purpose, inputs, and what is computed — all of which it does. The missing piece is disambiguation from the many nearby geometry siblings.

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 the baseline is 3. 'Inputs: number of sides, side length' restates the two schema properties without adding unit, integer, or range semantics beyond what the schema already declares.

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 names a specific verb and resource — 'Compute area, perimeter, and apothem of a regular n-gon' — which is narrowly scoped and distinguishable from generic siblings like calculate_area or calculate_perimeter. It stops short of explicitly contrasting itself with those siblings, so it doesn't reach a 5.

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 geometry or tiling' gives an implied domain hint but names no alternatives and no when-not conditions (e.g., 'use calculate_area for non-regular shapes'). The list_bundles pointer is a discovery aid rather than real usage routing, so this sits at minimum-viable.

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