withings_get_heart

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

Despite no annotations, the description discloses key behaviors: always fetched live (not cached), requires specific devices, returns ECG list with timestamps and AFib classification, and explicitly excludes raw waveforms. Minor omission: no mention of pagination or rate limits, but given simplicity of tool, transparency is high.

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?

Concise yet comprehensive: first sentence states purpose, then caching behavior, device requirements, parameter details in a clear list, return summary, and alternative tool. 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?

Given only 2 optional parameters and an output schema, the description covers all essential aspects: input semantics, output contents, behavioral constraints, and sibling differentiation. No gaps.

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 coverage is 0%, but description fully compensates: specifies date formats ('YYYY-MM-DD' or '30d' for start, 'YYYY-MM-DD' for end), defaults (last 30 days, today), and purpose (define date range for ECG recordings). Adds meaning beyond schema's basic string type.

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?

Clearly states the tool fetches 'ECG recordings and atrial fibrillation detection results', distinguishing it from sibling tools like withings_get_body (resting heart rate trends) and withings_get_sleep. The verb 'Get' and specific resource are explicit.

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?

Provides explicit guidance: requires a Withings device with ECG capability (ScanWatch, BPM Core), and advises to use withings_get_body or withings_get_sleep instead for resting heart rate trends. No ambiguity about when to use this vs. alternatives.

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