get_activity_timeseries

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

With no annotations, the description carries the full burden. It discloses the accepted values for resource and period, which is useful behavioral context. However, it does not describe the return format, pagination, authentication needs, or any side effects. The output schema likely covers returns, but other behavioral aspects remain opaque.

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 extremely compact, with the primary purpose front-loaded in a single clear sentence followed by concise parameter options. Every word earns its place, and there is no redundant information.

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?

For a simple 2-parameter tool with an output schema, the description covers the essential aspects: purpose and parameter constraints. It does not clarify the distinction from get_daily_activity, but the name and description imply a time-series focus. Given the simplicity, it is reasonably complete, though it could benefit from a brief note on typical use cases or output shape.

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?

Schema description coverage is 0%, so the description must compensate. It explicitly enumerates valid values for both resource (steps|distance|... ) and period (7d|30d|... ), providing crucial constraints not in the schema. It does not explain the meaning of each value, but the lists themselves are sufficient for correct parameter selection in most cases.

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 'Get activity trends over time' which identifies the specific verb and resource. The resource and period value lists further define the scope, distinguishing it from sibling tools like get_daily_activity or get_heart_rate.

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 gives clear context for when to use this tool: for activity trends over time. It does not explicitly mention alternatives or exclusions, but the phrase 'over time' implies longitudinal data, which differentiates it from daily snapshots. No direct comparison to siblings, so it falls short of a 5.

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