get_heart_rate

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It does not mention any side effects, permissions, rate limits, data retention, or return format beyond the vague 'resting HR and time in zones.' The read-only nature is implied by 'Get' but not explicitly guaranteed.

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 concise and front-loaded, consisting of two short sentences that immediately convey the tool's purpose and key outputs. There is no redundant information or filler.

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?

Despite having an output schema, the tool description is incomplete. It lacks context about the date parameter, any limitations or constraints, and how the returned data might be filtered or formatted. For a tool with a single optional parameter, the description fails to integrate that parameter into the overall usage 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?

The schema has one parameter (date) with zero coverage, and the description does not mention this parameter at all. It fails to explain how date affects the data returned, whether it's required for a specific range, or what the default behavior is. This lack of compensation for low schema coverage is a serious gap.

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's purpose with a specific verb and resource ('Get heart rate data') and further defines the scope by mentioning the specific metrics returned ('resting HR and time in zones'). This distinguishes it from sibling tools focused on sleep, weight, or activity data.

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 guidance is provided on when to use this tool versus alternatives such as get_daily_activity or get_health_snapshot. There are no usage scenarios, prerequisites, or exclusions mentioned.

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