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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so safety is covered. The description adds useful behavioral detail about the summary's contents, including Body Battery charge/drain contributors and longest stressful spells. It does not disclose data freshness or timezone, but against existing annotations this is still a solid contribution.

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 description front-loads the summary contents in one sentence, then uses a compact Args block for the only parameter. Every phrase contributes to knowing what the tool returns or how to set the date.

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 optional date parameter with an output schema, the description gives enough: it defines the summary's included data and explains all accepted date forms. Annotations cover safety, and the output schema carries return structure.

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% and the date parameter has no schema description. The description fully compensates by specifying YYYY-MM-DD, 'today', 'yesterday', offset syntax like '-3', and the default to today.

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 opening sentence names a concrete resource and scope — one day's health summary — and enumerates the included metrics (steps, calories, resting heart rate, Body Battery, stress). It does not explicitly contrast with siblings like get_readiness, get_sleep_data, or get_activities, so it is clear but lacks sibling differentiation.

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?

No sentence states when to choose this summary over get_readiness, get_sleep_data, or get_activities, nor any exclusions such as dates without data. The only implied use is a daily overview, which is insufficient explicit guidance.

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