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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=false, and destructiveHint=false, so the safety profile is covered. The description adds only that the tool estimates a pool and grades seed quality, with no details about calculation behavior, precision, limits, or output shape beyond what the annotations provide.

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 description is short and front-loads the core function in the first sentence. The second sentence is a promotional external link that does not help an agent invoke the tool, which slightly weakens conciseness but does not make it verbose.

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 three-parameter calculator with full schema coverage and safety annotations, the description is adequate. However, no output schema exists, and the description says only that it estimates and grades, without indicating what the return values look like or how the grade is expressed.

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 schema already documents all three parameters thoroughly. The description references lookalike percentage and market population, which map to two of the inputs, but adds no syntax, constraints, or interpretation beyond the schema.

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 and resource: 'Estimate the addressable pool' plus 'grade seed audience quality.' It is clear what the tool does, but it does not explicitly differentiate itself from related sibling calculators such as retargeting_pool_size_estimator or total_addressable_market_estimator.

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?

There is no guidance on when to use this tool versus alternatives, nor any stated prerequisites or exclusions. The description implies usage through the required inputs, but an agent must infer the appropriate context on its own.

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