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

Annotations already declare destructiveHint=true, idempotentHint=true, and readOnlyHint=false. The description adds useful behavioral detail beyond those annotations: partial update semantics, empty-string clearing, notes length limit, and the password alternative. It is consistent with the destructive annotation.

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 compact and informative, with the main purpose and field list front-loaded. The first sentence is somewhat long, but the extra clauses earn their place by covering all updatable fields and the password exclusion.

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 9-parameter mutation tool with annotations and no output schema, the description covers the essential behavior: what can be changed, how to clear fields, and where to go for passwords. Remaining gaps around tags/label semantics and return behavior are minor given the annotations and lack of an output schema.

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 coverage is only 33%, so the description must carry meaning, and it does: it identifies the mutable fields, groups them into identity details and usage metadata, states that notes are up to 2,000 characters, and explains empty-string clearing. It does not fully document tags or label behavior, but it adds substantial semantic value over the schema alone.

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 ('Changes') and resource ('a test account's details') and enumerates the mutable fields, making the tool's scope clear. It also distinguishes the password case by routing to set_password, which is a relevant sibling.

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 gives clear operational guidance: send only fields to change, use an empty string to clear a field, and use set_password for password changes. It does not explicitly contrast with create_address or delete_address, but the context for when to use this tool is clear.

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