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

readOnlyHint=true already tells the agent this is a safe read, so the bar is lower. The description adds genuine value by attributing the data to HM Land Registry, which sets expectations about coverage and freshness. It says nothing about result volume (single property vs. many postcode transactions), date-range coverage, or rate limits.

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?

A single front-loaded sentence with no filler, naming the source and the keys first. It is efficiently sized, though it is arguably so terse that the missing usage and return-shape context needed somewhere else in the definition.

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?

With no output schema and only a readOnlyHint annotation, the description carries the burden of explaining what comes back, yet it never says whether a postcode query returns one transaction or a list, nor what fields accompany a price. The data-source attribution partially compensates, but a three-parameter lookup tool with a list-shaped result needs more.

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 the three parameters are fully documented in the schema and the baseline is 3. The phrase 'a property or postcode' merely echoes two of the three inputs and adds no syntax, format, or precedence detail beyond what property_id's schema entry already explains.

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 names a specific dataset ('HM Land Registry Price Paid transaction history') and the two lookup keys ('a property or postcode'), which distinguishes it from siblings like get_epc_history and get_planning_history by data source. It is not merely a restatement of the name. It lacks an explicit verb and never distinguishes itself from search_property or get_property_summary, 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?

There is no when-to-use guidance, no exclusions, and no named alternative among the ten siblings. The only routing hint ('Prefer this over re-supplying a postcode once you have it') lives in the property_id schema entry, not in the description. An agent must infer from the name alone when this tool beats get_property_summary.

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