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

Beyond the readOnlyHint annotation, the description discloses key behaviors: results are limited to snapshot coverage, bulk and commercial sales are included by default, provenance fields like older_records_exist and sample_complete must be checked, and empty results are coverage-limited. This rich context helps the agent avoid drawing incorrect conclusions about property history.

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?

The description front-loads the core purpose and then adds only high-value operational details: coverage, unfiltered behavior, filtering options, and caveats. Each sentence contributes essential information, and the formatting with bold caveats makes the critical warnings stand out.

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?

The description is complete for a read-only query tool: it explains ordering, coverage limits, default filtering behavior, how to restrict by property type, how to interpret empty results, and which alternative to use. Since an output schema exists, detailed return-value documentation is not needed, and the prose still references the key provenance fields.

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?

With 0% schema description coverage, the description carries the full burden for parameters. It defines property_type with all accepted letter values and explains that limit controls 'up to `limit` most recent transactions'. Postcode is understood from the tool's purpose, and requiredness is already in the schema.

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 opening sentence states a specific verb and resource: 'Land Registry Price Paid transactions for a postcode, most recent first.' It also differentiates itself from sibling tools by defining its scope and by explicitly naming property_comps as the alternative for clean comparable sales. This leaves no ambiguity about what the tool does.

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?

The description explicitly states when to use the tool and when not to: it is unfiltered by default, property_type can restrict results, and 'For clean residential comparable sales, use property_comps.' It also warns not to interpret an empty result as 'never sold', providing concrete decision guidance for the agent.

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