garmin_today

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

With no annotations, the description carries the full burden, and it does convey that the tool summarizes seven health metrics for a day, which implies a read-only retrieval operation. It does not disclose caveats such as data availability, sync requirements, timezone handling, or explicit side-effect-free behavior beyond what the schema states.

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 front-loaded summary line with a metric list; zero filler. The format is easy to scan and every phrase carries information.

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 tool with one optional parameter and an output schema, the description plus schema is nearly complete for correct invocation. It fully covers what data the summary contains, though it would be slightly stronger with an explicit read-only statement and a routing note separating it from sibling metric tools.

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 only parameter (date) has 100% schema coverage with an ISO format and a default-to-today description, so the schema already handles parameter semantics. The description adds no date behavior of its own, but it does not need to.

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 a daily summary resource and enumerates the included metrics (steps, calories, intensity minutes, resting HR, stress, Body Battery), so an agent can recognize the aggregate nature. It lacks an explicit verb like 'retrieve' and does not directly contrast with single-metric siblings, which prevents a 5.

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 phrase 'Daily summary' implies this is the tool for a composite same-day overview, and the sibling list shows single-metric alternatives, but the description gives no explicit 'use this instead of garmin_stress' guidance and states no exclusions. The agent must infer when this tool should win over siblings.

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