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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds the material context an agent needs: credit cost, the asking-vs-achieved distinction, gross-only yield with the items excluded, and that LHA is a benefit cap rather than a market rent. This is well beyond annotation coverage.

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?

Purpose is front-loaded, then basis definitions, then yield caveat, then LHA, then workflow/cost. Dense but nearly every sentence adds a caveat an agent would otherwise get wrong; it is long-ish but justified.

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?

An output schema exists, so return shapes needn't be described, and the description covers the interpretive hazards (basis labels, gross yield, LHA cap) thoroughly. The gap is the undocumented `beds` parameter, which leaves a small but real hole in an otherwise complete definition.

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 0%, so the description must compensate. It explains the `uprn` parameter's semantics well (an identifier, not an address, plus the resolution workflow) but never mentions the optional `beds` parameter or its role in the bedroom-band logic. Half of the parameters are effectively undocumented.

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 precisely what the tool returns: what the property would let for, plus the basis behind each figure and a gross yield. It also differentiates itself from siblings by explaining that `unit_hedonic` does not exist and by pointing at `lha_rate` concepts and valuation siblings implicitly.

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?

Explicit routing: keyed on a UPRN, so call `address_autocomplete` (free) to narrow then `address_resolve`. It also states UK-only scope and the 5-credit cost, and gives concrete instructions on what to quote (p25–p75 with area_asking) and what not to present (gross as net).

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