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

Annotations already declare readOnlyHint=true, openWorldHint=false and destructiveHint=false, so the safety profile is covered. The description adds real value by disclosing the output composition and the 3-bundles-per-square factor, but says nothing about the defaults (pitch/waste of 0) or the shape of the returned values. Solid but modest beyond annotations.

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?

A single sentence that front-loads the calculation source and then enumerates the derived outputs with their key conversion factor. No filler, nothing that could be cut without losing information.

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 deterministic four-parameter calculator with full schema coverage and no output schema, the description adequately explains what is consumed and what is produced, including the bundle conversion. Only the defaulting behavior and a note on the overlapping area/pitch siblings are missing.

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%, so length, width, rise (per 12 run) and waste percent are all documented in the schema itself. The description echoes footprint/pitch/waste without adding syntax, units, or default behavior beyond what the schema already states, so the baseline 3 applies.

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 resource (roof area from footprint and pitch) plus the concrete outputs it derives (roofing squares, approximate shingle bundles). It is clearly distinct from numeric siblings like square_footage or slope, though it never says so explicitly. A resolver can tell what it computes without reading 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?

No when-to-use or when-not-to-use guidance, and no mention of overlapping siblings (square_footage for raw area, slope for pitch math). Usage is only implied by the name. For a pure calculator this is tolerable but it is a genuine gap.

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