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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so the safety profile is fully covered. The description adds no behavioral context beyond "Returns premium estimate," which the output schema already carries — no assumptions, no accuracy caveats, no input constraints are disclosed.

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?

Short and mostly front-loaded, but the input list is duplicated in the first and third sentences with no added value, and one of those duplicate lists is wrong. It is tight in size but not in information quality.

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 four-required-parameter tool the description omits coverage_level entirely and invents a trip_cost input, so an agent reading only the description would not call the tool correctly. The presence of an output schema excuses not describing return values, but the input-side gaps are not excused.

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 would be 3, but the description actively misleads: it claims "trip cost" is an input when no such parameter exists, uses "region" for the enum parameter destination, and never mentions coverage_level, one of four required inputs. This introduces error rather than meaning.

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 (estimate travel insurance cost) and the factors it depends on, which is enough to distinguish it from generic calculators. However it makes no attempt to distinguish itself from the near-identical sibling calculate_travel_insurance (or calculate_insurance_estimate), leaving the agent to guess which one to call.

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?

"Use for trip planning" is a vague context with no exclusions or alternatives. The only routing hint, "See list_bundles for related 'voyage' calculators," points at a bundle-listing tool rather than an alternative calculator, and the obvious competing sibling calculate_travel_insurance is never mentioned.

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