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

Annotations already establish read-only, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds genuinely non-obvious context: the specific standards applied, the returned dimensions, and notably that HUD cost cards expose missing price cells rather than silently dropping them. It stops short of describing precision, rounding, or failure modes for invalid rises.

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?

Three sentences, front-loaded with the core purpose before the output enumeration and the disclaimer. The middle sentence is a dense list of six outputs and one clause ('separate historical HUD accessibility cost cards with missing price cells visible') is awkwardly worded, but nothing is redundant.

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 carries the return-value burden and does list the main outputs (run length, width, landing, rise-per-run, handrail dimensions) plus the ancillary cost cards. For a single-parameter tool with full schema coverage this is nearly complete; only rounding/precision and the shape of the cost-card payload remain unstated.

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% and the schema already defines rise_inches, its positive lower bound, and the fact that the computed run excludes landings and door maneuvering space. The description's 'from entrance rise' restates this without adding format, unit, or range guidance, 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 verb and resource — 'Plan wheelchair ramp length from entrance rise' — and anchors it to ADA 2010 §405.2, which no sibling calculator does. The tool is unmistakably distinguishable from the many generic numeric calculators in the sibling list.

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?

The closing sentence 'This is a planning guide, not a code inspection' gives one explicit when-not boundary, which is useful. However, there is no positive usage framing, no prerequisites, and no routing to alternatives for related questions (e.g. cost estimation tools like driveway_cost or concrete_calculator).

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