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

Annotations already declare that this is not read-only and not destructive, so the agent knows it is a mutation. The description adds only the source of the ID and says nothing about what the rename affects, whether it is reversible, or any permission requirements. It does not contradict the annotations, but it provides little behavioral context beyond them.

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 a single front-loaded sentence with no filler. It is appropriately concise for the tool, though it could carry slightly more useful context without becoming bloated.

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 with two parameters and no output schema, and the description correctly points to list_muscle_groups for the ID. However, it does not explain the new-name parameter or the mutation's behavioral implications, leaving an agent to infer key details from the schema and annotations.

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 coverage is 50%: muscleGroupId is documented as coming from list_muscle_groups, but the name parameter is undocumented in both the schema and the description. The description repeats the ID source but does not clarify that 'name' is the new name or add any constraints for it.

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: renames a muscle group. It also identifies the source list for IDs, which helps distinguish it from create_muscle_group and list_muscle_groups. It is clear, though it does not explicitly contrast with the sibling rename tools.

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 phrase 'from list_muscle_groups' implies the prerequisite that the ID must come from that list. However, there is no explicit when-to-use guidance, no exclusions, and no explanation of when to choose rename_muscle_group versus create_muscle_group or other rename tools.

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