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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so safety is covered. The description adds useful behavioral context beyond annotations: GB companies receive AIA/WDA guidance from official rates, while other countries receive a jurisdiction note, and the output is framed as a hint rather than a computation.

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 are front-loaded with the core purpose, scope, jurisdiction behavior, and the key usage condition. There is no redundant or filler language.

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?

For a low-complexity, read-only hint tool with full schema coverage and rich annotations, the description supplies enough context: what it returns conceptually, how UK vs non-UK behavior differs, and what it explicitly is not. No output schema is present, but the description adequately frames the expected result.

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 both parameters are already documented in the schema. The description reinforces that the hint applies to a specific fixed asset, but it does not add parameter-level meaning beyond what the schema provides.

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?

The description states a specific verb and resource: retrieving a tax capital allowance hint for a fixed asset, with the book-depreciation-vs-tax-relief distinction. It clearly bounds the tool as guidance rather than a filing computation, which separates it from computation and reporting siblings.

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 gives explicit trigger conditions: when the user asks about capital allowances, AIA, or tax relief on a specific asset. It also states a clear exclusion — not a filing computation — but does not name a specific sibling alternative for that case.

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