get_heart_rate_timeline

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

With no annotations, the description carries the burden and discloses important behaviors: readings are downsampled to ~max_points evenly spaced samples, and last_reading gives the newest value Garmin has. It does not cover timezone handling or data availability nuances, but the key behaviors are transparent.

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 compact, front-loaded with the core purpose, and uses a clear Args section. Every sentence adds value without fluff or repetition.

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 tool with an output schema and only two optional parameters, the description covers purpose, usage, parameter semantics, and key behavioral details. Minor gaps remain around timezone interpretation and sampling edge cases, but nothing an agent needs to invoke it correctly is missing.

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%, but the description fully documents both parameters: date format with default, and max_points with default and a helpful semantic cue (~15 min apart). This compensates completely for the sparse schema.

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 returns intraday heart rate for a day, including the most recent synced reading. It uses a specific verb and resource and distinguishes it from sibling tools like get_resting_heart_rate by emphasizing the timeline and recent-reading aspect.

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?

It gives explicit usage guidance with examples like 'what is my heart rate now / this morning / at 15:30', which tells an agent when this tool is appropriate. It does not explicitly name alternatives or when-not-to-use scenarios, but the context is clear.

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