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

The description adds significant behavioral context beyond the annotations, such as error handling when location is not found, assurance that figures are never nationwide fallbacks, and details on price units per search type. Annotations already indicate read-only and idempotent, so the description enriches this.

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 informative and well-structured, starting with the primary action and then adding important details. While it is slightly lengthy, every sentence serves a purpose; a bit more conciseness would be ideal.

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 presence of an output schema, the description provides necessary context: return values are explained, error cases are covered, and price units are clarified. It is complete for an agent to use correctly.

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?

The description explains the purpose of all three parameters beyond the schema's coverage (67%). It clarifies that search_type filters by rental vs sale and explains price unit implications, adding value over the schema alone.

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 states that the tool returns aggregate market context for a Spanish area, including specific metrics like active listings, median price, etc. It distinguishes itself from sibling tools like search_properties by focusing on market summaries rather than individual listings.

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 explicitly advises using this tool before recommending a price or commenting on listing value, providing clear context. It does not explicitly state when not to use it, but the context is sufficient for an agent to decide.

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