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

Annotations already cover read-only, idempotent, open-world and non-destructive traits. The description adds real value beyond them: it discloses the output form (plain numbered text with amendment and commencement notes), the point-in-time behavior, and a rate/cost limit (free within a daily allowance, then $0.003 USDC per call via x402).

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 tight sentences with no filler: the capability is front-loaded and the cost/scope caveat follows. Every clause carries information.

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 an output schema present, the description need not explain return values, and it adequately covers granularity, date behavior and cost. Only the relationship to sibling legislation tools is unaddressed, which is a minor gap.

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 all five parameters are already documented in the schema. The description reinforces the date parameter's 'today or past date' semantics but adds no syntax or format detail beyond what the schema provides — baseline 3.

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: retrieving 'plain numbered text of one section, regulation, article or schedule paragraph'. The granularity ('one ... paragraph') implicitly distinguishes it from whole-item retrieval, but no sibling such as uk-legislation__item or uk-legislation__search is named to make the boundary explicit.

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?

It indicates the applicable context ('as it stands today or on a past date') and discloses the cost model, which is genuine usage information. However, it never says when to pick this over the sibling item/search/changes tools, so selection guidance is only implied.

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