Update Email Account

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

Annotations already cover the safety profile (readOnlyHint=false, idempotentHint=true, destructiveHint=false), and the description adds genuinely new behavior: partial-update semantics ('Only provided fields change; omitted fields keep their current values') and the failure mode for passwords ('field-specific errors naming the password field'). It does not mention required permissions or what happens when the domain/local part is not found, so it stops short of full disclosure.

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?

Four compact sentences with the core purpose front-loaded and no filler. Slight redundancy is the only flaw: the 8-72 character password constraint is already in the schema and is partially repeated here, though it is attached to new error-behavior 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?

An output schema exists, so return values need not be explained, and the mutation semantics are covered. However, for a partial-update mutation with five parameters there is no mention of authorization requirements, domain-existence preconditions, or side effects of lowering a quota below current usage — gaps an agent would want closed.

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 100%, so the schema already documents every parameter including ranges and patterns; the baseline is 3. The description does add two pieces of meaning beyond the schema: that unspecified optional fields are left untouched, and that the 'user' local part is resolved case-insensitively. The password length/strength restatement duplicates the schema.

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?

Opens with a specific verb+resource plus the exact mutable fields: 'Updates a mailbox's password, storage quota, or daily send limit.' That clearly distinguishes it from create_email_account, get_email_account and delete_email_account in the sibling list, though it never names an alternative 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?

Usage is implied rather than stated: the agent can infer this is the tool for changing an existing mailbox's password/quota/limit. There is no explicit 'use this instead of X when Y', no stated prerequisite that the domain and mailbox must already exist, and no guidance on when not to call it.

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