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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=false, so the safety profile is covered. The description adds meaningful behavioral detail beyond that: the four return categories and the specific 80% 'approaching' threshold, which the annotations do not convey.

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 comparison, then status definitions and use cases in a compact form. The closing sentence ('Limits are set in Control > Comfort Limits') partially restates the opening 'Control tab' reference, minor redundancy.

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 read-only, single-optional-param tool with an output schema, the definition covers purpose, statuses, and use cases adequately. The only gap is lack of explicit sibling routing, which is minor given the distinct concept.

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% with a single optional entity_id whose omission semantics are already documented in the schema. The description adds no further parameter syntax or format detail, so the baseline 3 applies.

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 ('Compares current net FX exposure against per-currency comfort limits') and clarifies scope. It is clearly distinguishable from sibling get_fx_exposure by adding the limit-comparison dimension.

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 gives concrete use cases via quoted questions ('are we within limits?', 'which currencies need attention?'), which grounds the when-to-use. However, it does not explicitly name alternative sibling tools (e.g., get_fx_exposure) or state when-not to use it.

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