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

Annotations already signal read-only, idempotent, and non-destructive behavior. The description adds valuable behavioral detail beyond that: exact display-name matching is case-insensitive, and the tool returns an all_valid indicator plus invalid names with up to 3 close catalog matches as suggestions. This clearly sets expectations for how the tool behaves.

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 concise and front-loaded: it starts with the core purpose, then covers matching rules, return behavior, and workflow guidance. Every sentence adds relevant information without redundancy or 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?

Given the simple 1-parameter schema, existing output schema, and clear annotations, the description is complete enough. It explains what the tool validates, how names are matched, what it returns, and when it should be used in the broader workout-creation workflow.

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 describes the single parameter as 'Exercise display names to validate' with 100% coverage. The description adds meaning by specifying that names must be exact display names, case-insensitive, and that invalid entries will receive suggestions. This enriches the schema's basic description.

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 purpose: checking whether exercise names exist in the exercise catalog or custom exercises. It specifies the exact matching criteria and distinguishes the validation role from sibling tools like search_exercises and create_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?

The description explicitly instructs when to use this tool: before proposing a workout with create_workout, and provides an alternative path by taking names directly from search_exercises results. It also sets a firm rule that proposals must never contain nonexistent exercises, leaving no ambiguity about the tool's intended workflow placement.

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