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

The annotations already declare readOnlyHint, idempotentHint, destructiveHint, and openWorldHint, covering the safety profile. The description adds no behavioral context beyond what annotations provide—no note about rate limits, output format, or authentication needs. It merely restates the purpose.

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 directly states what the tool does. The second sentence is a promotional link to an external calculator website, which does not help an agent invoke the tool and slightly detracts from conciseness.

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?

Given a simple calculator with three numeric parameters, full schema coverage, and no output schema, the description does mention the key outputs: days until fatigue and the date to have fresh creative ready. It could be slightly more explicit about the return format, but it is largely complete for this tool's 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%, so the input schema fully documents each parameter with meanings like 'fatigue frequency ceiling' and 'audience / reach size'. The description adds no additional parameter context, so the baseline of 3 applies when the schema does the heavy lifting.

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 (forecast) and resource (days until ad audience hits fatigue frequency ceiling, and date for fresh creative). It is clear what the tool computes, but it does not explicitly differentiate itself from similar siblings like ad_frequency_risk_checker or creative_testing_duration_forecaster.

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 no guidance on when to use this tool versus alternatives. It does not state prerequisites, exclusions, or name any sibling tool that could be used instead. Usage is only implied by the tool's purpose.

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