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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds genuine non-structural context: the 5-credit cost, the UK-only scope, the UPRN keying constraint, and crucially the three-valued semantics distinguishing verdicts (true/checked_false) from non-verdicts (defaulted_false/not_checked) that must be reported as such.

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-loads the purpose and the critical three-valued caveat before the long parenthetical coverage list. The enumeration is dense but each domain listed earns its place by telling the agent what the report contains; only minor trimming is possible.

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-value structure need not be described. With a single required parameter, the description covers scope, cost, keying, acquisition workflow, and interpretation rules. It is essentially complete for correct invocation, missing only sibling-routing guidance.

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 there is one parameter, so the description must carry the semantics. It does the most important thing: clarifies that the argument is a UPRN identifier, not an address string, and points to address_resolve as the way to obtain one, preventing a common misuse.

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+resource and enumerates the exact domains covered (flood, coal, heritage, environmental, planning, infrastructure), which implicitly distinguishes this composite report from single-domain siblings like property_flood_risk or planning_designations. The three-valued framing ('What this property is in, and whether we actually checked') makes the deliverable unambiguous.

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?

Gives clear operating context: UK only, costs 5 credits, keyed on a UPRN not an address, and a concrete prerequisite chain (address_autocomplete then address_resolve). It does not explicitly state when to prefer this over property_report, property_summary, or the domain-specific siblings, so the exclusion guidance is missing.

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