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

With no annotations, the description carries the full burden and does disclose real behavioral traits: returned content varies with whether a key is supplied, and the call costs no quota (a useful cost/rate signal). It omits prerequisites — e.g. whether an onboarding session must already exist, what happens if none does, or auth requirements beyond 'a key'.

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?

Three short sentences with the primary content front-loaded and no filler; the quota note earns its place because it is actionable. The phrase 'With a key' is terse to the point of ambiguity about what kind of key.

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 parameterless tool with no output schema, the description adequately sketches the return payload (question ids, options, prior answers) and notes cost. What it lacks is the undeclared key's nature and any error/prerequisite conditions, but the core of what an agent needs in order to call it is present.

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?

The schema is an empty object, so the baseline would be 4, but the description references 'a key' that does not appear anywhere in the input schema. That introduces a parameter the agent cannot see or pass explicitly, creating ambiguity about whether it is an ambient credential or an undocumented argument.

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 names the resource precisely — the onboarding questions that complete account setup — and specifies returned fields (ids and options) plus the conditional addition of already-given answers. It is clearly distinguishable from answer_onboarding and describe_signup. It is a noun phrase rather than an explicit verb, which slightly weakens it.

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 only implied: an agent can infer this is the lookup to perform before calling answer_onboarding, and that supplying a key reveals prior answers. There is no explicit when-to-use, when-not-to-use, or named alternative such as describe_signup, so the agent must infer the routing.

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