get_metrics

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

Annotations already establish read-only, idempotent, non-destructive, open-world behavior, so the safety profile is covered. The description adds that output is raw normalized records with source metadata, which is useful since there is no output schema, but says nothing about volume limits, pagination, or how deduplicate/aggregate_daily alter results.

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?

Three short sentences, zero filler, and the primary action is front-loaded before the pointer to the helper tool. Nothing repeats the schema or the annotations.

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 7-parameter query tool with no output schema, the description at least sketches the return shape, but it leaves the agent without guidance on cost of wide ranges, conflict resolution behavior, or how aggregation changes granularity. Adequate as a minimum, not complete.

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 100%, so all seven parameters including enums, defaults, and examples are already documented. The description only restates the date-range and multi-metric aspects at a high level, adding no behavioral meaning beyond the schema (e.g., how source_priority interacts with deduplicate).

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?

States a specific verb (read) and resource (Google Health API v4 metric types) plus the scoping parameter (date/time range), which differentiates it from snapshot/summary siblings. It does not explicitly distinguish itself from closer siblings like get_recent_metrics or get_trends, so the boundary is only implied.

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?

Explicitly routes the agent to list_available_metrics for valid metric names, which is concrete and actionable. It gives no guidance on when to choose this versus get_recent_metrics, get_body_metrics, or get_trends, so it falls short of full when/when-not coverage.

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