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

readOnlyHint=true already tells the agent this is a safe read, so the bar is lower; the description goes further by specifying that it is the *authenticated* account (implicitly requiring a valid credential) and by naming the concrete fields that come back. It stops short of describing rate limits, error behavior, or auth failure modes, but adds genuine context beyond the 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?

Two short sentences, front-loaded with the core purpose and followed by the concrete return fields plus the underlying REST endpoint. Every clause earns its place with no filler.

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 zero-parameter read tool with an empty schema, the description is nearly sufficient: it names the resource, the auth scope, and the fields returned, which partially compensates for the missing output schema. It could be marginally stronger by stating that it always returns a single account object rather than a list.

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 tool takes zero parameters, so there is nothing for the description to disambiguate and the baseline of 4 applies. The brief field list in the description is useful but does not map to any input.

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?

States a specific verb (Get) and resource (authenticated Acuity account's profile), and even enumerates the returned fields (name, email, timezone, plan, currency). This clearly distinguishes it from every sibling, all of which operate on appointments, clients, calendars, or catalog data rather than the account itself.

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 implies usage ('authenticated account's profile') but never says when to reach for this tool or how it relates to siblings. That said, no sibling provides account-level data, so the absence of an explicit alternative pointer is a minor gap rather than a real ambiguity.

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