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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint=false, so the safety profile is fully covered without the description. The description adds only what is computed, with no mention of assumptions, unit handling, or limits; with annotations carrying the load, a 3 is appropriate.

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 tight sentences with the core computation front-loaded and no filler. The second sentence is a navigational pointer whose value is modest but non-zero, keeping it just short of a 5.

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?

An output schema exists, so return values need not be explained, and all four params are documented in the schema with units and defaults. The safety profile is covered by annotations. The only real gap is that the description does not help an agent decide between this and the adjacent calculate_roof_area sibling.

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 each of the four parameters documented including units and defaults, so the baseline is 3. The description adds no additional parameter meaning (e.g., how pitch or load feeds the calculation) beyond what the schema already states.

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 pairs a specific verb ('Calculate') with a specific resource ('roof truss') and names the outputs (dimensions, rafter length, material quantities) scoped to a pitched roof, which distinguishes it from the sibling calculate_roof_area. It stops short of explicitly naming a sibling to differentiate against, so it is clear but not maximally disambiguating.

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 pitched-roof scope; there is no statement of when to choose this over calculate_roof_area or calculate_beam_load. The 'See list_bundles for related construction calculators' line is a discovery pointer rather than a when/when-not rule, so it earns partial credit at best.

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