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

readOnlyHint=true already establishes this is a safe read, lowering the burden. The description adds the concrete return contents, which is genuinely useful context, but discloses nothing about authorization scope, pagination, or error behavior for an invalid clientId.

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?

Two tight sentences with zero filler; the return-value summary is front-loaded and the parameter guidance follows immediately. Nothing is redundant with the schema or annotations.

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?

With no output schema, the description takes on the job of describing what comes back and does so by naming the key metrics. Combined with the alias clarification, an agent has enough to invoke it correctly; only the distinction from adjacent client getters is left implicit.

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 carries the full parameter burden, and it does so well: clientId is identified as the client's user _id, the same value used by every other tool, and userId is flagged as an accepted alias. This resolves the ambiguity of two overlapping optional string params that the schema leaves completely undocumented.

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 ('Get a client's fitness profile') and enumerates the computed metrics returned (BMI, TDEE, recommended calories, weights), so an agent knows what it produces. It implicitly separates itself from the self-scoped get_my_profile by saying 'a client's', but never names a sibling explicitly.

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 tells the agent which identifier to pass and that userId is an alias, which is useful invocation guidance, but gives no when-to-use versus when-not guidance relative to get_my_profile, get_client_preferences, or the other client getters in the sibling list. Usage is implied rather than stated.

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