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 fully covered. The description adds the return semantics ('area in input-units squared'), which is useful, but nothing about validity constraints or error behavior across the shape variants.

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 short sentences, front-loaded with the core purpose, with no filler. The trailing bundle pointer is the only mildly expendable sentence.

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, and the tool is a pure read/compute with no side effects, meaning the annotations plus description cover the essentials. The remaining gap is which dimension parameters each shape requires, a real hazard given only 'shape' is required and additionalProperties is false.

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 each of the 10 parameters has a short label, so the baseline is 3. The description adds no shape-to-dimension mapping, which is the one piece of semantics the schema genuinely lacks — 'width/height' vs. 'length/height' vs. 'semi_major/semi_minor' per shape is left entirely to inference.

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 ('Compute area for common 2D shapes') and enumerates the shape family, which cleanly separates it from calculate_volume, calculate_perimeter, and calculate_ellipse in the sibling list. An agent can pick this tool 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?

Gives context ('geometry, real estate, or paint estimates') but never says when NOT to use it or which sibling to prefer — e.g., calculate_ellipse exists separately yet ellipse appears in this tool's own enum, and calculate_paint_needed/calculate_paint_quantity are the natural siblings for the paint use case cited. The 'See list_bundles' pointer is a weak routing hint rather than real guidance.

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