withings-mcp

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It effectively communicates important behavioral traits: 'Always fetched live from the Withings API (not cached due to large signal data)' explains freshness and performance characteristics, and 'Does not include raw signal waveforms' sets expectations about data completeness. However, it doesn't mention error conditions, rate limits, or authentication requirements.

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 well-structured and appropriately sized. It begins with the core purpose, then provides important behavioral context, followed by parameter details and return value information, ending with clear usage guidance. Every sentence earns its place with no wasted words, and the information is front-loaded effectively.

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 the tool's moderate complexity (2 parameters, no annotations, but has output schema), the description is mostly complete. It covers purpose, prerequisites, behavioral traits, parameter semantics, and usage guidelines. The output schema will handle return value details, so the description appropriately focuses on what's not covered elsewhere. Minor gaps include lack of error handling or authentication information.

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?

With 0% schema description coverage, the description fully compensates by providing comprehensive parameter semantics. It explains both parameters (start_date and end_date), their formats ('YYYY-MM-DD' or '30d'), default values ('last 30 days' and 'today'), and their purpose in filtering ECG recordings. This adds significant value beyond what the bare schema provides.

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's purpose: 'Get ECG recordings and atrial fibrillation detection results.' It specifies the resource (ECG recordings and AFib results) and distinguishes from siblings by mentioning ECG capability and excluding raw waveforms. The verb 'Get' is specific and appropriate for a retrieval operation.

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 provides explicit guidance on when to use this tool vs alternatives: 'For resting heart rate trends, use withings_get_body or withings_get_sleep instead.' It also specifies prerequisites: 'Requires a Withings device with ECG capability (ScanWatch, BPM Core).' This clearly differentiates it from sibling tools and provides context for appropriate usage.

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