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

readOnlyHint=true already covers the safety profile, so the description's remaining duty is extra behavior. It usefully discloses the default sort (by milestone threshold) and that nested perks/entry rewards are opt-in, but says nothing about pagination, result limits, or auth requirements.

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?

One compact sentence with the resource, sort order, and optional inclusion all front-loaded; the API endpoint reference is short and non-redundant. No wasted words.

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 simple zero-required-param read tool with no output schema and full schema documentation, the description covers the essentials. It only lacks minor operational detail like pagination behavior, which is a small gap at this complexity.

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% and the single optional enum-array param is fully documented in the schema. The description restates the include purpose ('optionally with each tier's perks and entry rewards') but adds no format or defaulting nuance beyond the schema. 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 ('List the VIP program's tiers') and adds distinguishing scope detail: sorting by milestone threshold and optional nested data. No sibling overlaps with VIP tiers, so an agent can identify this tool's job immediately.

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?

Usage is implied by the description (fetch the tier list, optionally with nested data) but there is no explicit when-to-use/when-not, no prerequisites, and no named alternative. Adequate but leaves routing to inference.

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