get_hrv_dataRetrieve Heart Rate Variability (HRV) for a specific date to assess recovery and stress levels. Get daily HRV metrics directly from Garmin Connect.
Get Heart Rate Variability (HRV) data for a specific date. HRV measures the variation in time between heartbeats, indicating recovery and stress levels.
| Name | Required | Description | Default |
|---|---|---|---|
| date | No | Date in YYYY-MM-DD format. Defaults to today if not specified. |
Changes observed during successful MCP inspections.
v4.3.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and openWorldHint=true, so the description doesn't need to restate safety. It adds context about what HRV measures (recovery/stress), which is useful. However, it doesn't disclose return format, units, or any edge cases (e.g., missing data behavior), which would be valuable for a health metric 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 sentences, front-loaded with the core purpose, and the HRV explanation is concise and relevant. No wasted words.
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 is simple (1 optional param, no output schema), and the description covers the purpose and metric meaning. However, it lacks information about what the response contains (e.g., values, units, time intervals) and any caveats about data availability, which would be helpful for a health data tool. Given the simplicity, this is adequate but not complete.
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 100% (the date parameter is fully described with format and default behavior). The description adds the meaning of HRV but doesn't add parameter-specific details beyond the schema. Baseline 3 is appropriate since the schema handles parameter documentation.
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 HRV data for a specific date and explains what HRV measures. It distinguishes itself from sibling tools like get_heart_rate and get_stress_data by focusing on HRV specifically, though it doesn't explicitly name alternatives.
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 HRV data on a given date but doesn't explicitly state when to use this over alternatives like get_heart_rate or get_stress_data. The context of recovery/stress levels is mentioned, providing some guidance, but no exclusions or alternative tool references are given.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.