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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds real value beyond that: the exact return fields (value with unit, percentile, confidence with reason, source, observation period) and the upstream publisher behind each category. It does not mention rate limits or coverage gaps within the three nations.

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-loaded with the core purpose and output shape, then a single dense sentence mapping categories to sources. Every clause carries information, though the category list partially duplicates the schema enum and the sentence is long enough to be awkward to scan.

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 compensates by describing the return shape and field set, and it bounds the service area to England, Wales and Scotland. Combined with annotation-covered safety and a fully-described schema, an agent has enough to call it correctly; pagination and result-size limits remain unstated.

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%, so the baseline is 3. The description exceeds it by attaching provenance to each category value (crime = police.uk, deprivation = IMD/WIMD/SIMD with domain deciles/rank/score, property = HM Land Registry, environment = EA/NRW/SEPA), which meaningfully enriches the enum beyond the schema's bare list.

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 and resource ('Returns the signals of one category for a place') with geographic scope, and explicitly anchors itself to the sibling get_area_signals by promising the same output shape. An agent can distinguish it from get_area_signals without opening either schema.

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?

The description implies usage by naming the parent tool's shape ('same shape as get_area_signals') and enumerating the seven categories, but never states the selection rule — e.g. 'use this instead of get_area_signals when you need only one category' — nor any prerequisites or exclusions. Usage is inferable but not spelled out.

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