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

Annotations already establish it as a safe, read-only, idempotent operation. The description adds useful context by disclosing the analytical behavior: it computes metrics across a date window and detects movement and new entrants. This goes beyond the schema and gives insight into what the tool produces, without contradicting any annotations.

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 two concise sentences plus an example question, front-loaded with the core purpose and followed by a concrete use case. Every sentence adds value and there is no redundancy.

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?

While the purpose and output (covered by an output schema) are clear, the description does not fully address the parameter space, especially since schema descriptions are missing. It gives a strong example but leaves questions about defaults (e.g., rangeDays default 30, limit default 25) and parameter meanings, making it partially complete for a 7-parameter tool.

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?

The schema has 7 parameters with 0% description coverage, placing the burden on the description to explain parameter meanings. The description only vaguely implies date-window (rangeDays) through 'date window' and uses 'French Music' in the example, but does not explain `end`, `limit`, `genreId`, or how parameters interact. This is insufficient for a schema of this size.

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 clearly states the tool's function: 'Which apps dominated a chart over a date window' and enumerates specific metrics (median rank, best rank, days present, days at number one, movement against previous window, new entrants). It also gives a concrete example question, 'Who moved into the French Music top 10 this week?', which uniquely identifies this tool's purpose among siblings.

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 explicitly says, 'This is the tool for 'who moved into the top 10 this week',' providing a clear use case. It doesn't mention alternatives or when not to use it, but the example and phrasing give adequate usage guidance without naming exclusions.

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