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: the caching mechanism ('Returns one entry per day from the local cache by default'), the need to sync first, the option for live API fetching, and the sorting of results. It doesn't mention rate limits or authentication requirements, but covers the core 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 efficiently structured with clear sections: purpose statement, behavioral notes, parameter explanations, and return value description. Every sentence adds value - no wasted words. It's appropriately sized for a tool with 3 parameters and complex caching behavior.

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 (caching behavior, date formatting, sibling differentiation) and the presence of an output schema (so return values don't need explanation), the description is complete. It covers purpose, usage guidelines, behavioral context, parameter semantics, and distinguishes from siblings - all essential elements for an agent to use this tool correctly.

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 must fully compensate. It provides detailed semantics for all 3 parameters: start_date format options and default, end_date format and default, and live parameter purpose. The description adds substantial value beyond the bare schema, explaining format constraints and behavioral implications.

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 daily activity summaries (steps, distance, calories, active time).' It specifies the exact metrics retrieved and distinguishes it from sibling tools by explicitly stating 'Not for workout sessions -- use withings_get_workouts instead.' This provides specific verb+resource differentiation.

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 versus alternatives: 'Not for workout sessions -- use withings_get_workouts instead.' It also gives important prerequisites: 'Run withings_sync first to populate the cache' and explains the default behavior versus live fetching. This covers when/when-not scenarios clearly.

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