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 and does so effectively. It explains the caching behavior ('Returns measurements from the local cache by default'), the live API fetch option, the prerequisite action ('Run withings_sync first to populate the cache'), and the return format ('Returns measurements sorted by date, one entry per measurement group'). It doesn't mention rate limits or authentication requirements, but provides substantial behavioral context.

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 efficiently organized. It starts with the core purpose, then explains behavioral aspects, provides detailed parameter documentation, and ends with exclusion guidance. Every sentence serves a clear purpose with no redundancy. The information is front-loaded with the most important details first.

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 complexity (4 parameters, caching behavior, API interaction) and the absence of annotations, the description provides complete context. It covers purpose, usage guidelines, behavioral aspects, parameter semantics, and sibling tool differentiation. The presence of an output schema means the description doesn't need to explain return values, and it appropriately focuses on the tool's operational context.

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 documentation. It explains all 4 parameters with clear examples and defaults: date formats ('YYYY-MM-DD', 'YYYY-MM', or '30d'), metric options with a complete list, and the live parameter's purpose. The description adds significant value beyond the bare schema, which has no parameter descriptions.

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 body composition measurements (weight, fat, muscle, etc.)'. It specifies the exact resource (body composition measurements) and distinguishes it from sibling tools by explicitly mentioning what it's NOT for: 'Not for sleep or activity data -- use withings_get_sleep or withings_get_activity instead.' This provides clear differentiation from related tools.

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 excellent usage guidance with explicit when-to-use and when-not-to-use instructions. It states: 'Returns measurements from the local cache by default. Use live=True to fetch directly from Withings API. Run withings_sync first to populate the cache.' It also explicitly names alternatives: 'Not for sleep or activity data -- use withings_get_sleep or withings_get_activity instead.' This gives the agent clear decision criteria for tool selection.

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