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

Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true and openWorldHint=false, so safety is covered. The description does add a real behavioral fact beyond them: the tool opens nothing by itself and returns step-by-step instructions, which the agent would otherwise not know. However, the closing sentence about the official REST API is unrelated to this tool's behavior and muddies rather than clarifies.

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 lead sentence states an action the tool apparently does not perform, so the reader must revise their understanding mid-paragraph. The final sentence about Intervals.icu having a public REST API earns no place in a tool definition and adds noise. Structure is not front-loaded around the tool's actual behavior.

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?

With no parameters and no output schema, the description carries the burden of explaining what comes back, and it does partially ('screens, buttons, fields'). What remains missing is the shape of that return value and how it relates to the actual wellness data, leaving the agent unsure whether a follow-up data call is needed.

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 input schema has zero parameters and 100% coverage, so there is nothing for the description to disambiguate. Baseline 4 applies for a no-parameter tool.

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 name and title say 'List wellness', but the description immediately undercuts that by saying it 'Returns how to do it in Intervals.icu step by step (screens, buttons, fields) and opens nothing by itself'. An agent cannot tell whether this tool returns wellness records or a procedural how-to guide, which is a materially different purpose. It names the resource domain (Intervals.icu wellness) but no sibling such as intervals_icu_log_daily_wellness is referenced for contrast.

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?

There is an implied workflow: call this to get steps, then 'do it with the cotlet_browser_* tools in the user's Intervals.icu Cloud Browser'. That is genuine sequencing guidance, but no condition states when to use this versus the other Intervals.icu list tools, and nothing says when not to use it.

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