withings_trends

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

With no annotations, the description carries the transparency burden. It states the computation/return behaviour and the auto-sync side effect, but it does not fully spell out whether the sync mutates local storage or whether network access may occur; the mention of auto-sync implies this but leaves some ambiguity.

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 organised but contains some redundancy: 'Computes averages, min/max, and changes over time' is repeated as 'Returns aggregated averages with change indicators'. Still, it is concise overall and easy to scan.

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?

The description covers purpose, parameters, return content per data type, and explicitly routes raw-data requests to sibling getter tools. It also clarifies the cache/sync context, making it self-contained for an agent deciding between this tool and its siblings.

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?

Although the input schema lacks descriptions, the prose explains every parameter: data_type options, period enum/default, start_date/end_date formats and defaults, and compare format including the rule that compare overrides the other date parameters. This is more than enough for an agent to fill the arguments correctly.

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: analysing trends in cached health data with aggregates (averages, min/max, changes). It explicitly distinguishes itself from raw-data getters by naming the alternative 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?

It gives concrete guidance on when to use the tool (trends/aggregates) and when not to use it ('Not for raw data -- use withings_get_body/sleep/activity instead'). It also explains the auto-sync behaviour when the cache is stale, providing useful context for invocation.

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