Google Health Physical-Time Rollup

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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, so the safety profile is clear. The description adds no new behavioral context—no mention of pagination, timezone handling, supported data types, or return format. It essentially restates the tool's title.

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 a single, brief sentence with no fluff. It is front-loaded with the action verb. However, it is so terse that it borders on under-specification, though for conciseness it earns high marks.

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?

Despite having an output schema and 10 parameters, the description is far too minimal. It fails to explain the meaning of 'physical time intervals', the relationship to daily rollup, or any behavioral nuances. An agent would be under-informed for correct selection and invocation.

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 60%, meaning 4 of 10 parameters lack descriptions. The tool description offers no parameter explanations at all, leaving gaps for page_size, page_token, response_format, and data_source_family. Since coverage is moderate, the description should have compensated but did not.

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 states a specific verb 'aggregate' and resource 'data type over physical time intervals', which distinguishes it from the sibling 'google_health_daily_rollup' by the 'physical time' qualifier. However, it does not explicitly name the alternative or contrast with daily rollup, so it stops short of full 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 no guidance on when to use this tool versus alternatives. It doesn't mention physical vs. daily intervals, prerequisites, or contexts where one should be preferred. Given the sibling 'google_health_daily_rollup', a clear opportunity for usage guidance is missed.

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