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

Annotations already declare read-only, idempotent, open-world and non-destructive, so safety is covered. The description adds genuinely new behavioral context beyond that: the latency expectation ('a cold lookup can take up to a minute') and the fact that results include confidence, calculation method, comparables and tax liability.

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?

Two sentences, zero filler; the return payload is front-loaded and the operational caveat (one-minute cold lookup) is placed last where it is most useful. Nothing repeats the name or title.

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, the description carries the burden of describing returns and does so adequately, plus a latency warning. It is nearly complete for a single-parameter read tool, though it omits failure modes (e.g., what happens for an unresolvable address_id).

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 100% and the single parameter is fully documented as a 'DAR address UUID from search_address'. The description's mention of taking an address_id from search_address merely restates the schema, adding no format or constraint detail.

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 scope: 'Statistical market-value estimate for one Danish home', which cleanly separates it from get_postcode_sales (an aggregate sibling) and search_address (an ID lookup). The enumerated return contents (value, range, confidence, comparables, tax) further pin down what the estimate comprises.

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 a prerequisite chain — the address_id must come 'from search_address' — which implies a sensible call order. However, it never states when to prefer this over get_postcode_sales or when the estimate is inappropriate (e.g., non-residential properties), so usage is only implied rather than explicit.

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