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

Annotations already declare destructiveHint=true and idempotentHint=true; the description's contribution is the partial-update guarantee, which usefully narrows what 'destructive' means here (fields not supplied are untouched). It does not explain what makes the operation destructive, whether prior values are recoverable, or what is returned, so the added behavioral context is real but thin.

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 sentence with the resource and the partial-update constraint front-loaded; no filler, no restatement of the tool name.

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 mutation tool with no output schema, the definition covers identity, scope, and partial-update semantics, and the annotations carry the safety profile. It leaves open what happens with zero arguments (all parameters are optional), whether validation errors or a no-op result, and what the response contains — meaningful gaps for an agent deciding whether to call it.

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 20% across 5 parameters, but names plus enums and numeric bounds make heightCm, weightKg, bloodType and biologicalSex largely self-explanatory; dateOfBirth even carries a format description and pattern. The description adds the important semantic that all fields are optional and only supplied ones are written, but says nothing field-specific beyond that.

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?

States a specific verb and resource ('Update ... health profile') scoped to 'the signed-in user's Vitalli hub', which separates it from the read-only sibling vitalli_get_health_profile and from other domains' profile tools (vora, stackwell). It does not explicitly name the read sibling or say how it differs from stackwell_update_health_context, so it falls short of full sibling differentiation.

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?

Usage is only implied: the parenthetical '(only the given fields change)' tells the agent this is the tool for partial edits, but there is no explicit when-to-use/when-not guidance and no mention of the read sibling for retrieval. An agent can infer the case, but nothing routes it deliberately.

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