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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world. The description adds cost (10 credits), UK-only scope, `not_available` behavior for underivable blocks with reasons, and an interpretation caveat that RV is a rating measure at the antecedent valuation date, not passing rent. These are valuable behavioral disclosures beyond annotations.

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 is appropriately sized for a complex multi-block report and every sentence carries information, but the first sentence is a long run-on enumerating report blocks, and the critical routing instructions (keyed on UPRN, call address_autocomplete) are placed at the end rather than front-loaded.

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?

Given a rich output schema, the description needn't detail return values, yet it still outlines report blocks and not_available reasons. It covers scope, cost, keying, and interpretation, though the parameter requiredness/selection ambiguity remains a gap for correct invocation.

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% and neither parameter has a schema description. The description names 'UPRN' and 'VOA UARN' and explains that the tool is keyed on UPRN and how to obtain one, but does not state whether one or both are required, what happens if both are supplied, or define UARN beyond the acronym. It adds partial meaning but leaves invocation ambiguity.

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 report keyed on UPRN/UARN and enumerates the report blocks (RV, sector indexes, income-basis value, auction history, owner, lease), so the agent knows what the tool produces. However, it does not explicitly distinguish this report from sibling tools that also expose commercial indexes or market data (e.g., commercial_index_series, commercial_market), leaving sibling selection partly implicit.

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?

Explicitly states UK-only scope, 10-credit cost, and the prerequisite workflow: call address_autocomplete (free) then address_resolve to obtain a UPRN, because the tool is keyed on UPRN not an address. It does not say when not to use this report or name alternative report tools, so it has clear context without exclusions.

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