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

With no annotations, the description must carry the behavioral burden. It does disclose that authentication is required and adds the important security instruction to never log or store the password. It does not mention potential side effects such as invalidating existing sessions or what happens to the current password, which would strengthen transparency.

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 three short sentences with no filler. The primary purpose is front-loaded, followed by authentication context, required parameters, and a critical security warning. Every sentence adds value.

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 simple action, the description covers purpose, required inputs, authentication, and security. However, there is no output schema and no description of what the call returns or what side effects occur on success, so the agent is left without full expectations for the tool's behavior.

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 needs to compensate for the undocumented mailboxId and password parameters. It does clarify that mailboxId comes from listMailboxes and that password is the new password, but it adds no format, length, or constraint details and omits mention of the optional sessionKey parameter.

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 clearly states the verb 'Set' and the resource 'a new password on a mailbox', making the tool's function immediately understandable. It is distinct from any sibling tool in the list, though it does not explicitly name or contrast an alternative such as createMailbox.

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 description gives useful context by requiring authentication and pointing to listMailboxes as the source for mailboxId. It does not explicitly explain when to choose this over alternatives or how the optional sessionKey fits in, so usage guidance is implied rather than fully explicit.

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