Polar Daily Training Summary

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so 'Read-only' largely restates structured data. The genuinely additive disclosure is 'non-medical', which frames the output as not clinical advice, plus 'when available' signalling graceful degradation when some data sources are missing. That is useful but thin for an aggregating tool.

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 with no filler, and the purpose is front-loaded before the read-only/non-medical caveat. Efficient, though arguably it errs slightly toward under-specification rather than conciseness.

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-value explanation is rightly omitted. However, for an aggregation tool spanning four data domains with no required parameters, the description does not clarify behavior when one or more domains are empty, nor default lookback interaction — leaving gaps an agent would reasonably want covered.

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 67%, with days and timezone documented in-schema and response_format left without a description. The description adds no parameter-level detail at all, so with coverage above the midpoint the baseline of 3 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?

States a specific verb ('Build') and resource ('daily summary') and enumerates the source data domains: sleep, activity, Nightly Recharge, and training. It is clearly distinguishable from polar_weekly_summary by scope, though the description never names that sibling explicitly to sharpen the 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 no when-to-use guidance, no named alternative (e.g. polar_weekly_summary, polar_wellness_context), and no stated preconditions such as required auth or connected device. The phrase 'when available' hints that source data may be absent but does not tell the agent when to prefer this tool over the list_* siblings.

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