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

Annotations already cover read-only, idempotent, non-destructive, and closed-world behavior. The description adds that the tool classifies frequency into healthy/caution/fatigue territory, which is useful output behavior beyond annotations. It doesn't detail auth or rate limits, but none are expected for a calculator.

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?

The first sentence is front-loaded and compact, but the second sentence is a promotional link that does not help an agent invoke the tool and therefore does not earn its place.

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 two-parameter calculator with no output schema, the description states the calculation and the output categories. Annotations cover safety. It is largely complete, though it does not define the numeric thresholds for the healthy/caution/fatigue classification.

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 parameters are fully documented in the schema. The description names impressions and reach but adds no syntax or format beyond what the schema already 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 (Calculate) and resource (average ad frequency from impressions and reach), and specifies the output classification (healthy/caution/fatigue). An agent can distinguish it from sibling ad_creative_fatigue_forecaster, which forecasts creative fatigue rather than frequency risk.

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?

No explicit when-to-use or when-not-to-use guidance, and no alternatives are named. Usage is merely implied by the tool name and calculation.

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