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

Annotations already declare readOnlyHint=true, so safety is covered. The description's enumeration of returned fields adds some value in the absence of an output schema, but says nothing about error behavior for an unknown clientId or field availability.

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?

One short sentence with no padding, but the missing verb makes it a noun-phrase fragment rather than a front-loaded action statement. Nothing is wasted, yet the most important information (that it fetches) is absent.

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 single-parameter read with no output schema, listing the returned fields is a useful substitute for return documentation. However, it omits the action verb and any not-found or permission context.

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?

With 100% schema description coverage, the schema already explains clientId as the 'Client's User _id (from list_clients)'. The description adds no parameter detail beyond that, which is the expected baseline.

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 fragment 'A client's name, email, phone and date of birth.' names the fields returned but never states a verb, so the read action is only inferable from the tool name. Listing email/phone/DOB does partially distinguish it from sibling readers like get_client_profile, but not 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?

No indication of when to call this versus get_client_profile, get_client_preferences, or the write-side sibling update_client_contact_details. The agent is left to infer the boundary from names alone.

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