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

Annotations already declare it read-only, idempotent, and non-destructive, so the safety profile is covered. The description adds genuinely useful behavior beyond that: it renders an interactive MCP app rather than raw rows and returns a short text summary alongside the visual view, which materially affects how an agent should present 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?

The metric list and range toggle are front-loaded in the first sentence, with usage and rendering guidance following. It is efficient overall, though 'When the user asks about this, prefer calling this tool' mildly restates the preceding preference sentence.

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?

An output schema exists, so return values need not be spelled out, and annotations carry the safety profile. The description covers purpose, usage, and the interactive rendering behavior; the only omission is explicit routing to the narrower week-level siblings an agent might otherwise pick.

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% with a single enum-constrained parameter, so the schema already documents 'range' and its 7d/30d/90d/1y values. The description restates the same enum values without adding syntax, defaults, or semantics beyond the schema — the baseline 3 applies.

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 ('Show') and resource ('health overview') and enumerates the metrics covered (steps, Zone Minutes, resting HR, HRV, VO2max, stress) plus the range toggle. It gestures at differentiation by framing itself as the 'broad' wearable/health-trend tool versus the narrower siblings, but never names an alternative.

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?

Gives a clear when-to-use condition ('Prefer this for broad wearable or overall health-trend questions') and a rendering preference over text output. It does not state when NOT to use it or name the competing narrower tools (e.g. show_week_steps), so the routing guidance is directional but not exhaustive.

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