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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description goes beyond that by disclosing the exact computation, including the ceiling rounding and the waste multiplier, which tells the agent this is a deterministic formula-driven tool with no hidden side effects.

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, zero filler, and the purpose is front-loaded before the formula. The dense formula is justified because it is the substance of the tool rather than padding.

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?

For a six-parameter deterministic calculator with no output schema, the description supplies the formula needed to interpret the result and the field roles needed to call it. It stops short of stating the return shape (a single integer board count) or the unit handling between the foot-based inputs and the inch-based formula.

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% with per-parameter defaults, so the schema already carries the parameter burden and baseline is 3. The description's formula adds some interpretive value by showing how width, gap, board length and waste combine, but it also introduces ambiguity, writing 'width(in)' and 'deck length' without reconciling them against the schema's foot-based fields.

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 computed quantity ('Number of deck boards') with a stated scope ('rectangular deck'), which is enough to separate it from the other calc_* material calculators in the sibling list. The description names the drivers (board width, gap) up front so an agent knows exactly what domain this covers.

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: an agent can infer this is the calculator for deck board counts, and no sibling overlaps this material, so there is little risk of misrouting. But the description gives no explicit when-to-use condition, no note that it assumes rectangular geometry, and mentions no alternative for non-rectangular or diagonal layouts.

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