garmin_heart_rate

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

With no annotations, the description carries full behavioral burden and does disclose non-obvious traits: it returns daily RHR plus a rolling 7-day average and flags days exceeding the rolling average by >5 bpm, with interpretation of those flags. It omits the standard traits (read-only nature, permissions, rate limits), but the analytical behavior and detection threshold are genuinely useful additions.

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?

Three tight sentences, front-loaded with the core purpose, then the return shape, then the anomaly logic. No filler or restatement of the name; each sentence adds information.

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?

For a single-parameter read tool with an output schema, the description covers purpose, return contents, and the anomaly heuristic, which is nearly everything needed to call it. The only gap is the undocumented 'days' parameter, which the output schema does not compensate for.

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?

One parameter ('days') exists with 0% schema description coverage and a default of 30, so the description is the only place semantics could be supplied. The description never mentions the configurable time window, so an agent cannot tell that the lookback period is adjustable or what unit it uses.

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 resource ('Resting heart rate') and specific analyses ('trend analysis and anomaly detection'), so the agent knows exactly what data it produces. However, it does not differentiate from close siblings like garmin_hrv, garmin_recovery, or garmin_health_summary, so an agent comparing H/R-related tools gets no routing signal.

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 a use case (spotting illness/overtraining from the anomaly flags) but never states when to call this versus garmin_hrv, garmin_recovery, or garmin_trends. No explicit when/when-not guidance or prerequisites are given, leaving the agent to infer selection.

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