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 adds meaningful behavioral context by explaining the exact formula, the standard 1.125 blocks per square foot coefficient, and how waste is applied. It stops short of describing output format or edge cases.

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?

The description is front-loaded with the purpose, then provides the formula and coefficient in two compact sentences. Every element directly supports understanding the calculation, with no filler.

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?

Given 7 optional parameters, no output schema, and read-only annotations, the description is largely complete: it explains what is calculated and how. It could explicitly note that all inputs are optional with defaults, but the core computation is clear enough for an agent to invoke.

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 schema by explaining how joint_in, waste_pct, and net wall area combine in the formula, giving functional meaning to several parameters rather than just repeating their definitions.

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?

The description states a specific calculation: number of 8×8×16 concrete blocks (CMU) for a wall. It distinguishes this from sibling calculators like calc_brick or calc_concrete_slab by naming the exact material and unit size.

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 tool name and the phrase 'for a wall,' but there is no explicit when-to-use, when-not-to-use, or alternative routing guidance. The description does not tell the agent when to choose this over other masonry calculators.

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