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

Beyond the annotations (readOnly=false, idempotent=true, destructive=false), the description discloses the partial-update behavior, the conditional return payload (notification fields vs insights), and the API key requirement. These are meaningful behavioral details not present in the structured fields.

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 dense but well organized: scope first, then usage condition, exclusions, return behavior, and auth. The long field enumeration is justified for an 11-parameter tool, and there is minimal filler.

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 and 11 parameters, the description still covers when to use it, what changes, what does not change, excluded alternatives, conditional return values, and authentication. An agent has enough context to select and invoke the tool correctly.

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 18%, so the description must compensate. It names all 11 parameters and groups them into notifications vs insights, which helps call selection. However, it does not explain acceptable values or deeper meaning for most fields beyond their self-evident names.

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 opens with a specific verb and resource: 'Update your account's preferences', then enumerates exactly which notification and insight fields are affected. It also names what the tool is not for, distinguishing it from configure_key and configure_services.

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 states the trigger condition explicitly: 'Use it when the owner's preferences change', and clarifies partial-update semantics with 'only the fields you pass change'. Exclusions with alternative tools are spelled out for keys, services, and billing.

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