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

With no annotations, the description carries full behavioral disclosure. It reveals that accounts created via register_account have no password by default, that the bearer token is the primary credential, that this is a one-time activation, that it validates password composition, and that already-set passwords produce a 409. This is strong transparent behavior even though it does not mention success response shape.

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?

Each sentence earns its place: one defines the target account, one explains the default state, one gives the intended usage, one states parameter constraints, and one covers the error condition and alternative. It is dense but tight and well-structured.

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 single-parameter tool with no output schema, the description is essentially complete. It tells the agent how to authenticate the operation implicitly via bearer token, why the tool exists, what the parameter needs, and what happens on repeated attempts. Nothing critical is missing for generating a correct call.

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 0%, so the description must compensate for the undocumented 'password' parameter. It does, by stating the format ('min 8 chars, letters+numbers') and clarifying that no current password is needed for the first call. This adds meaning beyond the schema's bare minLength constraint.

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 uses a specific verb ('Set a password') with a clear target resource ('THIS account' owned by the bearer token). It explains the contextual purpose (creating an email+password login recovery method) and distinguishes itself from the later use case of changing an already-set password.

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 explicitly states when to call this tool ('Call this ONCE'), what passwords the tool needs versus does not need ('no current password the first time'), and what to do if the password already exists ('use change-password instead'). This gives clear when-to-use and when-not-to-use guidance.

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