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

Annotations already cover the read-only/idempotent/non-destructive safety profile, so the description correctly spends its words on behavior: the expert-estimator sourcing, the per-unit basis (SF/LF/each/LS), the optional low-reliability public cross-checks, and the confidence-tag vocabulary returned in responses. That is meaningful context beyond the structured fields, though return shape details are left to the output schema.

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?

Purpose and the bid-use caveat are front-loaded, which is good, but the long comma-separated scope-item list largely duplicates the schema's scope examples and inflates the definition without adding callable information. Trimming that list would sharpen it.

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 an output schema present, the description sensibly avoids explaining return fields yet still discloses the confidence-tag scheme and the budget-only limitation. It is close to complete; only the distinction from sibling lookup tools is left implicit.

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 the schema already documents limit, scope, and include_public_crosschecks. The description's scope-item enumeration largely restates the schema's example values, adding only the 'low-reliability public cross-checks' nuance, so baseline 3 is appropriate.

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 verb and resource: 'Return 2026 US installed budget SELL price ranges' for a glazing scope item, which is clearly distinct from the knowledge/cross-reference siblings. It never explicitly names or contrasts those siblings, so it stops short of a 5.

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?

It gives an explicit when-to-use ('Budget/sanity-check use only') and when-not ('never for bids'), plus the caveat that ranges vary by region, scope and market. No alternative tool is named for cases where a bid-grade number is required, which keeps it below 5.

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