Retrieve overnight HRV metrics from Garmin Connect, including last-night average, 7-day average, baseline, and status, optionally for a specific date.
Overnight HRV: last-night average, 7-day average, baseline and status.
| Name | Required | Description | Default |
|---|---|---|---|
| day | No | YYYY-MM-DD; defaults to today | |
| raw | No | Return Garmin's full JSON instead of a summary |
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already establish readOnlyHint and openWorldHint, so the safety profile is covered. The description adds the meaningful constraint that this is overnight-only data, but says nothing about latency, data availability (e.g., what happens on a night with no reading), or how it differs from the sibling heart-rate tools.
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?
A single front-loaded sentence with no filler. It is efficient, though the list of returned metrics is largely redundant with the existing output schema.
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?
With an output schema present, the description need not enumerate return values, and annotations cover safety. What remains missing is the usage context and edge-case behavior (no data, timezone for 'day'), which leaves it merely adequate for a simple read tool.
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%, with 'day' (YYYY-MM-DD, defaults to today) and 'raw' fully documented in the schema. The description adds nothing about either parameter, so the baseline of 3 is correct.
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 names the resource (HRV) and narrows scope to overnight, which separates it from get_heart_rate and get_stress without needing the schema. It stays a fragment rather than a verb+resource statement, but the intent is 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?
There is no guidance on when to call this versus get_sleep, get_heart_rate, or get_health_range, and no prerequisites or exclusions. The agent must infer selection from the resource name alone.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.