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

Beyond the readOnly/idempotent/non-destructive annotations, it discloses page size (24 results), default ordering ('newest first unless sorted'), the fields returned, and a hard 4-page cap on a single search. It also explains the currency semantics of the price filters, including the rent-per-year market caveat. These are the behavioral traits an agent cannot infer from the annotations or schema.

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 sentences, front-loaded with the purpose and results shape, with no filler. The final sentence about euro pricing is slightly convoluted but earns its place because the unit ambiguity genuinely affects filter values.

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?

For a 15-parameter search tool with annotations but no output schema, the description covers result shape, ordering, pagination limits, and price-unit semantics, leaving the remaining filters (kind, town, text, areas, near, min_baths) to the well-populated schema. Nothing essential for correct invocation is 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?

Schema coverage is already 80%, so most parameters are self-documenting, but the description adds value by clarifying that price min/max are interpreted as a sale price or a monthly rent in euros, and that some markets quote rent annually. It also reinforces that filters ('narrow') are preferred over the page parameter, adding intent the schema does not convey.

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 and resource with scope ('Search homes for sale or to rent in one market'), which is clearly distinct from single-listing siblings like get_listing or compare_listings. It does not explicitly name any sibling to route the agent, so it stops short of a 5.

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?

'Up to 4 pages per search: narrow with filters rather than paging' gives concrete operational guidance on when to filter versus paginate, which is the key usage decision for this tool. There are no explicit exclusions or named alternatives, so it is clear context rather than full routing guidance.

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