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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered; the description goes further by exposing the actual computation — openings subtracted, waste multiplier applied, and coverage scaled by base/finish thickness. That is real behavioral disclosure an agent could not get from the annotations. It stops short of stating output rounding (whole bags) or the system-enum behavior.

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?

Purpose is front-loaded in the first clause before the formulas, and every sentence carries information. The formula notation is dense and slightly harder to parse than prose would be, but nothing is redundant.

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 five optional defaulted parameters, no output schema, and annotations covering safety, the description supplies what's missing: the full derivation and the two result quantities (base bags, finish bags). Only the rounding/whole-bag convention is left implicit, which is minor for a read-only estimator.

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 coverage is 100%, so the baseline is 3, but the description maps parameters into the formulas: openings_sqft is subtracted, waste_pct multiplies area, finish_in scales the 70 sq ft coverage, and base thickness drives the 20–24 sq ft range. The 'system' enum values (three, two_dense, two_porous) are never explained, which is the one meaningful gap.

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?

Opens with a concrete verb and resource — how many 80 lb bags of stucco for a wall — and immediately splits the answer into base coat and finish coat, which is exactly the distinction that separates it from neighbors like calc_mortar, calc_thinset, and calc_drywall. 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?

Usage is implied by the calculator framing: use it when you need stucco bag counts for a wall area. There is no explicit when-to-use statement, no when-not, and no reference to an alternative tool for related materials (mortar, thinset), so routing is left to inference.

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