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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, non-destructive, closed-world), so the bar is low and the description clears it: it discloses data provenance (HM Land Registry, police.uk, Ofsted, Environment Agency, ONS, Census 2021, IMD 2025), a 12-month sales window and five-year medians, and that every block carries caveats and a source citation. That is real context beyond the annotations, though it does not state failure behavior for an unknown district.

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 opening clause is well front-loaded and each enumerated block is arguably load-bearing for a data-heavy tool, but the body is a long run-on enumeration with no bullets or grouping, which makes it harder to parse than it needs to be. Content is justified; structure is not.

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?

There is no output schema, so the description bears the burden of describing the return payload, and it does so thoroughly across every data block, including windows, definitions and citation URL. The remaining gap is what happens on an invalid or non-London district input, which is not addressed anywhere.

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 100%, so the 'district' parameter is fully documented with format and examples in the schema; the description adds only the implicit scope ('one London postcode district') and no syntax or edge-case detail. This is the baseline 3 for a schema that does the heavy lifting.

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 (profile) and a precise resource/scope ('one London postcode district'), and the enumerated data blocks make it obvious this is a single-district deep-dive rather than a lookup or comparison. It never names a sibling (compare_london_districts, find_london_district, check_london_postcode), so the differentiation is inferred from scope rather than stated.

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?

There is no when-to-use or when-not-to-use guidance and no mention of alternatives, despite five plausible siblings that overlap (compare_london_districts, rank_london_districts, check_london_postcode). The agent must infer from 'one district' that this is not the multi-district or validation tool.

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