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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the safety profile is known. The description adds valuable behavioral detail beyond the annotations: it enumerates the exact fields returned, those excluded, and the behavior for clients owned by another organization (reported as not found). This enriches the agent's understanding of the response and error semantics.

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 description is composed of three clear sentences: purpose, returned fields, and excluded/edge-case behavior. It is front-loaded with the core purpose and is reasonably concise. It could be slightly tighter, but every sentence adds necessary context.

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 operation, the description covers the essential information: what will be returned, what will not, and an important edge case. Since an output schema exists (though not shown in prompt), the return field enumeration is a helpful supplement. Nothing critical for calling this tool is missing.

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 100%; the input schema already fully documents the clientId parameter (type, pattern, and source). The description repeats 'from list_clients' but adds no new meaning. With full schema coverage, the baseline of 3 is appropriate.

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 uses a specific verb 'Fetch' and names the resource 'tenant-scoped HairDora client', plus the identifier source ('from list_clients'). It clearly differentiates from sibling tools by stating exactly which fields are returned and which are excluded, making it impossible to confuse with list_clients or other get_* tools.

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 implies when to use it: after list_clients, and for workflow chaining. It doesn't explicitly exclude alternatives, but the context 'needed for client and appointment workflow chaining' and the exclusion of detailed fields give implicit guidance. It also notes the cross-organization not-found behavior, which helps callers handle errors.

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