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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds substantial behavioral context: it normalizes multiple listings into one response and explicitly handles known/estimated costs, availability, property facts, official checks, commute summaries, provenance, freshness, duplicates, constraints, and unknown fields.

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?

The core behavior is front-loaded and the description is a single sentence with no filler. The trailing list of output fields is long but each item contributes useful behavioral signal.

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?

The description covers input bounds, output shape, response normalization, and edge-case handling like explicit unknown fields. An output schema exists, so return values do not need to be explained further; the description is complete enough for correct tool selection and invocation.

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 baseline is 3. The description aligns with the ids parameter by mentioning two to eight listings, but it adds no meaningful detail about locale or parameter formatting beyond what the schema already provides.

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 ('Compare'), a precise resource ('listings'), and a bounded scope ('two to eight'). It also identifies the normalized AgentListing v2 response, which clearly differentiates it from single-listing tools like get_listing.

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 tool is clearly positioned for comparing two to eight listings, giving an agent a clear trigger condition. However, it does not explicitly name alternatives or state when not to use it, such as pointing to get_listing for a single listing.

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