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

Annotations already cover the safety profile (readOnlyHint, openWorldHint), so the bar is lower, and the description still adds genuinely useful behavior: it enumerates the preview groups returned and warns that recorded-sale results are incomplete for anonymous visitors when registration is prompted. That data-completeness caveat is exactly the kind of context an agent cannot get from 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?

Two tight sentences with the core purpose front-loaded and the return-group and completeness caveat following. No wasted words; only the absence of explicit sibling routing keeps it from a 5.

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 does not need to explain return values, yet it usefully summarizes the result groups and flags the anonymous-visitor limitation. Complete enough for an agent to call it correctly, with only routing guidance to siblings 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?

Only one parameter with 100% schema coverage, where the schema already documents it as a required free-text query up to 160 characters. The description restates 'free-text query' without adding format or syntax detail beyond the schema, so the baseline of 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 (search) and resource (StreetEasy's public mixed quick-search results), and names the actual result groups it aggregates. The word 'mixed' distinguishes it from the category-specific siblings like streeteasy_rentals_search and streeteasy_sales_search, though it never names those siblings 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: a free-text query suggests broad, cross-category discovery. There is no explicit when-to-use or when-not-to-use guidance relative to streeteasy_building, streeteasy_rentals_search, or streeteasy_sales_search, which are the obvious alternatives.

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