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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered by structured data and the description adds nothing on top. It does not explain what 'open' actually does for an agent (navigation vs. returning view content), nor whether the sidebar context matters. The only nuance is the mild tension between a navigation-sounding 'open' and readOnlyHint, which the description leaves unaddressed.

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?

A single short sentence with no filler, front-loaded with the verb and target. Nothing is padded or repeated from the schema.

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?

An output schema exists, so return values need no explanation, and the parameters are fully documented in the schema. What remains missing is the one thing only the description could supply: what opening a dashboard means relative to show_day and get_day_summary, and whether this is a UI navigation action. Adequate but with a clear gap for a tool sitting in a dense cluster of view-related siblings.

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 description coverage is 100%, and the schema already explains date format and today-default, babyId sourcing from list_babies and the single-baby fallback, and timezone fallback behavior. The description adds no parameter meaning beyond that, so the baseline 3 for fully documented schema applies.

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 verb-plus-resource is present ('Open the Nestling day view'), so the general purpose is legible, but the qualifier 'from the sidebar' describes a UI affordance rather than the tool's effect, and the description never distinguishes it from the close siblings show_day, get_day_summary, or open_quick_log. An agent cannot tell from this text which of those four view-related tools to pick.

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 no when-to-use guidance, no condition that selects this tool over show_day or get_day_summary, and no note on prerequisites. The single sentence gives the agent nothing to route on when several siblings plausibly open or summarize a day.

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