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

Annotations already declare this a safe, idempotent, closed-world read (readOnlyHint=true, destructiveHint=false, openWorldHint=false). The description adds a behavior the annotations cannot convey: bag counts are returned as whole bags (rounding-up semantics implied) for the two standard bag sizes, which directly affects how results should be interpreted.

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?

A single, densely packed sentence with no filler; outputs and input modes are front-loaded so an agent can judge relevance immediately.

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 an output schema present and full parameter documentation, the description does not need to spell out return fields, and safety is covered by annotations. It is complete enough to call correctly; the only minor gap is that the ft/m unit choice is left entirely to the schema.

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 every parameter (shape, length, width, diameter, area, depthInches, unit) is already documented in the schema. The description only reiterates depth in inches and the shape options, adding no new syntax, defaults, or constraints beyond the structured data. Baseline 3 applies.

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 (calculate) and concrete outputs (layer volume plus whole 2 cu ft / 3 cu ft bag counts) along with the accepted input shapes (rectangle, circle, or total area). This clearly separates it from volume_calculator or square_footage_calculator, though it never names an alternative to steer the agent between mulch vs gravel/concrete costing tools.

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?

The description implicitly tells the agent which input mode to pick (rectangle dimensions, circle diameter, or a pre-measured total area) and notes depth is in inches, which is useful context. However, it gives no explicit when-to-use/when-not guidance and does not point to any sibling tool as an alternative or prerequisite.

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