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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=true, so the safety profile is covered. The description adds useful behavior beyond annotations: it is informational not medical advice, costs $0.001 USDC per successful x402 call, and is also available over HTTPS. It also notes conditional behavior such as Karvonen zones when resting HR is given and Katch-McArdle when bodyFat is provided.

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 main purpose is front-loaded, and the long list is mostly substantive rather than filler. However, the core description is one extremely dense sentence enumerating many calculators, which makes it harder to scan and parse than a structured list would be.

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 high-complexity tool with no output schema, the description does list the kinds of results returned and the formulas used, which is helpful. It still lacks return structure and clear conditional input requirements, so an agent knows the broad outputs but not precisely which parameters unlock each one.

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 only 24% across 17 parameters, so the description must carry most of the parameter meaning. It hints at dependencies through calculator names (e.g. Navy body-fat implies neck/waist/hip, BMR implies age/sex/height/weight), but it never explicitly maps most parameters to the required calculations or explains when each optional input is needed. The agent is left to infer too much from a dense capability list.

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/resource (body and training calculator) and enumerates exact outputs such as BMI with WHO category, BMR formulas, TDEE, Navy body-fat, heart-rate zones, one-rep max, and running pace. An agent can immediately tell this is a fitness/biometric calculator rather than any sibling math or crypto tool.

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 clearly frames the tool as a one-call body and training calculator, metric or imperial, with an informational-not-medical caveat and pricing/HTTPS access details. It does not name alternatives or explicit exclusions, but no sibling tool in the list appears comparable, so the usage context is reasonably clear.

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