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

Annotations already disclose that this is a non-read-only, non-destructive, closed-world creation tool, and the description is consistent with that. The description adds workflow context about creating instances before create_workout and using exercise_id for stock/team exercises. However, it does not mention validation behavior, permissions, or what happens when the time_based/reps conditional is not satisfied.

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 tight sentences with no wasted text, and the core action is front-loaded. The follow-up sentence carries actionable workflow guidance rather than filler.

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?

An output schema exists, so return values need not be explained, and annotations cover the safety profile. Still, this is a 10-parameter tool with complex conditional requirements and 0% schema description coverage, and the description does not explain the time_based/reps/duration_seconds conditional or several optional parameters.

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 0%, so the description must compensate for 10 parameters. It explains the meaning of duration/reps, pace, weight, and RPE, which is useful, but omits important semantics for time_based, amrap, team_id, skip_intro, and the conditional relationship between time_based and duration_seconds versus reps.

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 (creates an exercise instance) and lists the key configurable dimensions: duration/reps, pace, weight, and RPE. It distinguishes the tool from create_workout by explaining that exercise instances are built first and their IDs are then passed into a workout.

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 clear usage context: use when building a workout manually, create instances per exercise, then pass instance IDs to create_workout. It also notes that stock and team exercises can be referenced directly via exercise_id. It does not explicitly exclude sibling tools such as create_rest_instance, so it falls short of fully explicit when-not guidance.

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