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

The annotations already establish that this is a safe read-only operation with no destructive or open-world behavior. The description aligns with that and adds usage context, but it does not add behavioral details beyond the annotations, such as localization behavior or result characteristics.

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 compact sentences with the purpose front-loaded and usage immediately following. There is no redundant or wasted text.

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?

The tool is simple, has an output schema, and has strong safety annotations, so the description does not need to explain return values or mutation risk. However, it omits the only parameter entirely and provides no sibling differentiation, leaving meaningful gaps for an agent invoking it.

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 sole parameter, locale, is undocumented in both the schema and the description. With schema description coverage at 0%, the description should explain what locale controls and what format is expected, but it never mentions the parameter.

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: it returns muscle groups for exercises. That is clear enough to distinguish it from most mutation siblings, but it does not explicitly differentiate itself from adjacent reference-list tools such as list_equipment or list_workout_categories.

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?

It gives concrete usage contexts: updating exercise metadata and filtering exercises. It does not state when not to use it or name alternative tools, so it falls short of full routing guidance, but the use cases are clear.

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