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

Annotations only declare readOnlyHint=true, so the description adds value by disclosing the AND-only filter semantics, the offset/limit paging model, and specifically that next_offset indicates where to continue — information not present in the annotations and important because there is no output schema. Missing: any note on result size caps or what happens with 30+ criteria, though the schema covers those bounds.

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?

Front-loaded with the purpose and the entity definition, then filter semantics, then paging, then example fields. Dense and mostly waste-free; the trailing POST endpoint adds little for an agent choosing a tool but is harmless.

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?

Five parameters, nested criteria objects, no output schema and no destructive behavior — the description covers purpose, filter logic, pagination continuation, and where field names come from, which is everything an agent needs to call it 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?

Schema coverage is 100%, so the baseline is 3; the description earns above that by listing concrete useful field names (property.system_search_key, property.adr_postcode, property.attr_bedrooms, etc.) that are not enumerated anywhere in the schema, and by clarifying the criteria AND-combination and next_offset continuation semantics.

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+resource and immediately disambiguates the entity: properties are 'the physical addresses behind listings, appraisals and tenancies', which separates it from rex_search_listings and rex_search_appraisals without opening either schema. The endpoint reference (POST /v1/rex/Properties/search) confirms the resource.

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?

Explains how to query (criteria combine with AND, only the 'in' type gives OR) and points to rex_describe_search_fields as the prerequisite for field names, which is real usage guidance. However, it never states when to use this tool rather than rex_search_listings or rex_get_property for a single record — the alternative routing is left to inference.

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