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

Annotations already cover readOnlyHint and openWorldHint, and the description adds genuinely new operational context: the data is public, it is scoped to exactly one listing, and each call costs 1 credit. It stops short of explaining caching behavior (despite a cache_max_age param) or what happens with a malformed or non-for-sale URL.

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 tight sentences with the resource and payload front-loaded and the cost note at the end where it belongs. The opening 'For-sale property details' largely restates the title, which is the only wasted phrase.

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 usefully enumerates the returned data fields, and the read-only/open-world annotations cover the safety profile. What is missing is only edge-case behavior (invalid URL, non-for-sale listing) and the meaning of the two undocumented optional parameters.

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 coverage is only 50% — url and tld are documented with an example and allowed values, but country_code and cache_max_age have no description anywhere. The description contributes nothing about parameters, so the two undocumented fields remain opaque and the description fails to compensate for the coverage gap.

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 names a specific verb and resource ('Public details for one Redfin for-sale listing') and enumerates the payload (price, specs, agent, price history, schools), so an agent knows exactly what it returns. The 'for-sale' qualifier implicitly separates it from redfin_forRent, but no sibling is named explicitly.

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: fetch this when you have a single listing URL. There is no explicit guidance such as 'use redfin_search first to find listing URLs' or 'use redfin_forRent for rentals', even though those siblings exist. The 'Costs 1 credit' note gives a cost threshold but not a when-to-use rule.

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