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

Annotations are sparse (readOnlyHint false, destructiveHint false), so the description carries the burden. It discloses the critical non-destructive guarantee ('original is never modified') and the ownership requirement. It does not specify whether a new workout record is immediately persisted or what the return value contains, but with an output schema present, that is somewhat covered. Overall, it adds meaningful behavioral context beyond the 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 with zero filler. The primary action is front-loaded, and the second sentence adds a crucial constraint. It is well-structured and efficient.

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 tool with a single parameter and an output schema, the description covers the core purpose, the key guarantee (original unmodified), and the ownership prerequisite. It does not explicitly state the return value or the fact that a new workout is created, but these are reasonably inferable from the tool's name and the existence of an output schema. Overall, it is sufficiently complete for an agent to use it correctly.

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 already documents the parameter (workout_id) with a clear description and source ('from list_workouts') and ownership requirement. The tool description adds no additional parameter-specific meaning, so with 100% schema coverage, the baseline of 3 is appropriate.

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 action (duplicate), the resource (existing workout), and the purpose (starting point for a new one). It also differentiates from creating from scratch by emphasizing it bases the new workout on an existing one, and explicitly mentions the original is untouched, which distinguishes it from update operations.

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 implies when to use it (when you want to create a new workout based on an existing one) and the ownership constraint ('this user owns'). It does not explicitly name sibling tools or provide 'when not to use' guidance, but the intent is clear enough from the phrase 'as the starting point for a new one'.

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