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

With no annotations, the description carries the full burden. It usefully discloses the 5-result free cap and 24h caching, which an agent would otherwise not know, but says nothing about auth, rate limits beyond the cap, error behavior, or data freshness beyond the cache window. 'Soft-Offer outbound is OFF' is unexplained jargon that adds little for an agent unfamiliar with the domain.

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 packed into three short fragments with little waste. The trailing 'Soft-Offer outbound is OFF' is opaque and arguably does not earn its place without explanation.

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 data-retrieval tool with no output schema, the description never indicates what a returned sale record contains (price, date, address, property type), leaving the agent guessing about response shape. The caching and cap notes are helpful, but the opaque soft-offer clause and missing return-value context leave real gaps.

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 description coverage is 100%, so both parameters (area, size) are already documented in the schema. The description adds only the example format 'M1' and reinforces the free max of 5, which the schema already states. Baseline 3 applies when the schema does the heavy lifting.

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: free preview of up to 5 HM Land Registry Price Paid sales by postcode/outcode/town, with an example (M1). The word 'peek' and the 5-result cap implicitly separate it from the sibling packs (price_paid_pack, area_comps_pack), but the description never names those alternatives explicitly.

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?

'Free peek' plus 'max 5 for free' implies this is the sample/trial path and that a full pack exists elsewhere, but no sentence says when to choose this over price_paid_pack or area_comps_pack. The agent must infer the routing from the tool names alone.

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