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

Annotations declare readOnlyHint=false, so the update behavior is expected. The description adds useful behavioral context by stating that omitted fields are not changed, which is important for callers. It also clarifies lack of destructive intent consistently with destructiveHint=false.

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 a single sentence that front-loads the action and then conveys the most important usage nuance. No filler or repetition of schema information.

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?

Given the 100% schema description coverage, an output schema, and annotations that rule out destructive behavior, the description is complete enough for an agent to call the tool correctly. It could add an explicit 'use for modifying existing clients' exclusion, but the current text is adequate.

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?

The schema already covers all 9 parameters with descriptions, so the baseline is 3. The description adds cross-cutting parameter semantics: only include fields to change, which clarifies how the optional properties behave during a partial update.

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 ('Update'), a specific resource ('existing client'), and the partial-update semantics ('only include the fields you want to change'). This clearly distinguishes it from create_client, get_client, list_clients, and archive_client.

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 phrase 'Update an existing client' gives clear context for when the tool applies, and 'only include the fields you want to change' signals a patch-style workflow. It does not explicitly name excluded alternatives, but the resource and action make the intended use obvious.

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