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

Annotations already indicate a safe, read-only, idempotent operation. The description adds behavioral context by stating it 'widens the comparison' and will explicitly note when the exact match is too thin, which informs the agent about output behavior.

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 description is two sentences, front-loaded with the tool's purpose, and contains no redundant filler. It conveys both the core function and an important behavioral nuance in a compact, well-organized manner.

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?

Given the tool's moderate complexity (3 params, nested object, no output schema), the description sufficiently communicates the nature of the returned data and the auto-widening behavior. It could be more explicit about the response format, but it covers the essential context.

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?

All parameters are described in the schema (100% coverage), so the baseline is 3. The description does not add specific parameter semantics beyond the schema; the 'widens the comparison' phrase relates to overall behavior rather than parameter usage.

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 clearly defines the tool as a price distribution for comparable items, including both asking prices and actual sale prices. The phrase 'Widens the comparison and says so when the exact match is too thin' distinguishes it from listing-search siblings and clarifies its role as a fair-price lookup.

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 description implies usage for price discovery ('What is a fair price?') and mentions widening comparisons, but it does not explicitly state when to use this tool over alternatives like search_market or compare_quotes, nor does it list exclusions.

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