polar_list_nightly_recharge

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

Annotations already indicate read-only, idempotent, non-destructive, open-world behavior, so the bar is lower. However, the description's phrase 'Always returns preprocessed sample data' is ambiguous and could be interpreted as returning non-real or incomplete data, which is a transparency concern not resolved by annotations.

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 is brief and directly addresses the tool's purpose. The repeated mention of 'preprocessed sample data' and listing the same metrics twice adds slight redundancy, but it is not overly verbose.

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?

Given no output schema, the description should explain more about returned data structure and any caveats. The 'sample data' phrase is unexplained and could leave an agent uncertain about the reliability or freshness of results, which is a significant gap in context.

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 100%, and the description clarifies the date range defaults and response format enum values. It adds useful context beyond the schema, though parameter behaviors like timezone handling are not mentioned.

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 clearly states the tool lists nightly recharge data and specifies the key metrics (ANS charge, HRV, recovery). It does not explicitly name sibling tools for differentiation, but the resource and action are clear.

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 description implies usage for retrieving nightly recharge data, but does not explicitly state when to choose this over alternatives like polar_get_sleepwise or polar_list_sleep. It also lacks context about the 'sample data' caveat, which could mislead an agent.

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