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

Annotations already declare readOnlyHint=true and openWorldHint=false, and the description adds value by disclosing the exact computation (average depth, 7.48052 gal/cu ft), letting the agent sanity-check results. It does not state unit assumptions or error behavior for negative/inverted depths, which keeps it below a 5.

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?

Two sentences: what it computes, then the exact formula. Zero filler and the scope qualifier is front-loaded.

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 no output schema, the description correctly names the output unit (gallons) and gives the full formula, and defaults live in the schema. It omits edge-case handling (flat-bottom pool where shallow equals deep, zero or inverted depths), which is a minor but real gap for a calculator.

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; the description goes beyond the per-parameter blurbs by explaining how shallow_ft and deep_ft are combined into an average depth and how length_ft and width_ft enter the product. It adds real semantic linkage rather than restating types.

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 (calculating gallons) plus a shape qualifier ("rectangular pool") and a geometric precondition ("sloped bottom, using average depth"). The word "rectangular" implicitly separates it from the oval and round pool-volume siblings, but no sibling is named explicitly.

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 only implied by the shape adjective; the description never says "use this for rectangular pools, use calc_round_pool_volume / calc_oval_pool_volume otherwise," nor does it address flat-bottom pools or other alternatives. An agent can infer the routing but must do the work itself.

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