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

Annotations already declare readOnlyHint=true and openWorldHint=true, and an output schema documents the return payload, so the listed fields (address, media, description, IDs, facts) add little. The one genuine addition is the conditional note that a listing URL yields those fields, hinting at ID-based fallback behavior, which is useful but thin.

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 sentences, zero waste: capability and options first, sibling routing second. Fully front-loaded and appropriately sized.

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 annotations covering safety, an output schema covering returns, and 100% schema coverage, the definition is nearly complete. Only the interplay between listing_id and property_id when no URL is supplied is left entirely to the schema, a minor gap.

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 url as the primary key and the listing_id/property_id pairing. The description reinforces that a URL drives the rich response but adds no syntax, precedence rules, or fallback detail beyond the schema, so 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?

Specific verb 'Fetch' plus resource 'Redfin property details,' and it explicitly names the sibling tools (redfin_search, redfin_similar, redfin_estimate) it is distinct from. An agent can place this tool precisely relative to its siblings without opening a 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?

It routes the agent by naming the three alternatives and their roles (search to find listings, similar for comps, estimate for valuation), implying this tool is for retrieving full details. There is no explicit 'when not to use' or prerequisite statement, so it falls just short of a 5.

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