health_get_ecg

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 discloses some behavioral details such as the waveform's size and the need for scaling and sampling rate, and that waveform samples may be null. However, it lacks information about cache behavior details (e.g., when live is false), potential errors, or rate limits, leaving a moderate gap.

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 well-structured with a brief overview, clear usage guidance, a compact Args section, and a return summary. Each sentence adds value and the description is front-loaded with the purpose, making it efficient and easy to parse.

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?

The tool has 4 parameters, no annotations, but an output schema that details the return structure. The description explains the purpose, usage, and key parameters; the output schema covers return values. It lacks some behavioral details (e.g., cache semantics, error cases), but it is sufficient for a health data retrieval tool, but not perfect.

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 0%, so the description must compensate. It does explain start_date and end_date formats and defaults, and describes the live and include_waveform parameters' effects. However, it omits the sampling_hz and scaling_factor fields from the parameter list (though they appear in the output), and doesn't provide full detail on date range conventions, so it partially compensates but not completely.

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 ECG readings from a watch, specifying the metric (single-lead trace, rhythm classification) and the main use case (heart rhythm or AFib checks). It also distinguishes itself from health_get_heart_rate, a sibling tool, by explicit contrast, making the purpose unambiguous.

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 explicitly states when to use this tool: for questions about heart rhythm or AFib checks, and when not to use it: for resting rate over time, for which health_get_heart_rate is recommended. This provides clear, actionable usage guidance and directly names the alternative, exceeding the minimum.

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