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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds the calculation basis (MET value × weight × duration), which tells the agent the result is a deterministic estimate derived from the exercise record, but it does not say what happens with an unknown id or whether MET data can be missing.

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?

A single tight sentence with zero filler, and the key qualifier (from MET value, weight, duration) is front-loaded. It reads as an incomplete fragment, but nothing is wasted.

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 simple read-only calculator with three fully documented parameters and no output schema, the description is adequate but thin. It does not state the output unit (kcal) or note that an invalid or missing exercise id will fail, which an agent would need before calling it in a loop.

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 100% — every parameter documents its type, units, and defaults — so the schema does the heavy lifting. The description adds only the implicit mapping that the id supplies the MET value; it gives no further detail on defaults or units beyond the schema.

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 names a specific resource (calories burned) and the exact inputs of the computation (MET value, body weight, duration), which clearly distinguishes it from the search/get/generate siblings in the toolset. It is a fragment rather than an explicit verb+object statement, but the intent is unambiguous.

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?

There is no guidance on when to call this versus alternatives such as get_exercise (which presumably returns MET data itself) or generate_workout. No exclusions, no prerequisites, no mention that the exercise id must exist in the catalog.

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