get_heart_rates

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

No annotations are provided, so the description carries the full burden. It mentions the return type (detailed time-series) and size (~25KB), which gives some behavioral expectations. It does not explicitly state side effects, but 'get' implies read-only, which is acceptable.

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 succinct, with the purpose, a distinguishing note, and parameter format all in a few lines. No unnecessary details.

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 simple get operation with one parameter, the description is complete. It provides the tool's purpose, output characteristics, and the parameter format. The contrast with the summary tool adds context without excessive length.

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 schema has one parameter (date) with no description, but the tool description adds 'Date in YYYY-MM-DD format', providing the required format and meaning. This fully covers the single parameter.

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 retrieves full heart rate time-series data for a given date, distinguishing it from the summary variant via 'full' and 'detailed'. The sibling list includes get_heart_rates_summary, which reinforces the distinction.

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?

Explicitly names the alternative tool get_heart_rates_summary() for compact summaries, implying this tool is for detailed data needs. The note about 2-minute intervals and ~25KB size further guides when to use it.

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