garmin_heart_rate

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

Annotations already declare readOnly, idempotent, non-destructive and open-world, so the safety profile is fully covered elsewhere. The description adds genuine context beyond that by specifying units (bpm) and the shape of returned data (resting/min/max values plus optional timestamped samples), but says nothing about behavior when data is missing for a day or about permissions/auth.

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 semicolon-linked sentence with the primary read stated first and the optional flag second. No filler, no redundancy with the schema or annotations.

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?

An output schema exists, so return-value detail is not required, and annotations cover the safety profile. What is left unaddressed is the meaningful ambiguity for this tool: what `day` means (timezone, historical range) and what happens on a day with no recorded data.

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 carries the burden for both parameters. It meaningfully explains include_samples as "timestamped samples," but leaves `day` entirely unelaborated — no timezone, date format, or whether it must be today or can be historical. Partial compensation only.

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?

States a specific verb ("Read") and resource (heart rate) plus the exact metrics returned (resting/min/max in bpm), which distinguishes it from the sibling garmin_heart_rate_zones. It stops short of naming that sibling explicitly, so differentiation requires the agent to infer it from the metric names.

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 use for a single day of heart-rate data and hints at the optional samples path, but gives no when-to-use vs when-not guidance and never points to garmin_heart_rate_zones or garmin_daily_summary as alternatives. Usage is inferable but not directed.

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