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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint=false, so the safety profile is fully covered without the description. The description adds only the 'Free' cost note and 'canonical record' framing; it does not disclose match-count behavior, region coverage limits, or what happens on no-match/ambiguous input. Adequate but thin against the annotation baseline.

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; the core action and canonical output are stated first. It is terse rather than padded, though the terseness comes at the cost of the missing details noted elsewhere.

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 values need not be explained, and annotations cover safety. Still, for a resolver that can return multiple candidates (max_results defaults to 5) and is UK-scoped by default, the description should say something about multiple matches and whether non-UK addresses are supported.

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 0% across three parameters. The description covers 'free-text address' (query) and implies a UK scope for country, but max_results is entirely unexplained and no format/default behavior for country is given. For a 0%-coverage schema the description should compensate, and it largely does not.

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 concrete verb ('Resolve') and resource ('free-text address to canonical record (UPRN)'), and the 'free-text' qualifier meaningfully separates it from address_by_postcode and address_by_uprn. It does not, however, mention address_autocomplete, the closest sibling, so sibling disambiguation is incomplete.

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?

'Resolve free-text address' implies the input situation (raw text with no postcode/UPRN yet), and 'Free' hints at cost considerations, which is why one would prefer it over a paid lookup. But there is no explicit when-to-use/when-not statement or named alternative such as address_autocomplete or address_by_uprn.

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