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 describes key behaviors: auto-sync behavior when cache is stale, what data is analyzed (trends vs raw), and what the tool returns (aggregated averages with change indicators). It doesn't mention rate limits, authentication needs, or error conditions, but covers the essential operational behavior well.

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 starts with the core purpose, explains parameters in a clear Args section, describes returns with examples, and ends with usage guidance. Every sentence adds value, with no redundant information or fluff.

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 (5 parameters, 0% schema coverage, no annotations, but with output schema), the description is remarkably complete. It covers purpose, parameters, returns, behavioral traits, and sibling differentiation. The output schema likely handles return format details, so the description appropriately focuses on semantic context rather than structural details.

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 detailed parameter semantics. It explains each parameter's purpose, options, defaults, and interactions (e.g., 'compare' overrides other date parameters). The description adds significant value beyond the bare schema, making parameter usage clear and actionable.

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: 'Analyse trends in cached health data' with specific verbs (computes averages, min/max, changes) and resources (body, sleep, activity data). It explicitly distinguishes from sibling tools by stating 'Not for raw data -- use withings_get_body/sleep/activity instead,' making the distinction clear.

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: 'Not for raw data -- use withings_get_body/sleep/activity instead.' It also explains when the tool auto-syncs ('Auto-syncs if the cache is stale') and clarifies parameter interactions ('When set, period/start_date/end_date are ignored').

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