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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds the default window size (52 weeks) and the anchoring semantics ('ending on end'), which is genuine behavioral context. It says nothing about auth requirements, rate limits, or whether partial weeks are included.

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?

Two short sentences, front-loaded with the return semantics and the window anchor. Every clause carries information and there is no filler.

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 read tool with readOnly annotations and no output schema, the description covers the essential contract: what is returned, the window, and the default. The remaining gap is the unresolved 'weeks' validation, which is handed off to a sibling rather than explained.

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 coverage is 50%: 'end' is documented in the schema, while 'weeks' has no schema description. The description compensates partially by disclosing the default (52) and pointing to getWeeklySteps for validation, but it defers the actual rules to another tool rather than stating units, bounds, or type, so the agent cannot fully resolve 'weeks' semantics from this definition alone.

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 names a specific verb+resource ('Weekly stress averages') and the aggregation window ('weeks weeks ending on end'), so an agent immediately knows it returns weekly-bucketed stress data. However, it does not differentiate from closely related siblings like get_stress_data, get_all_day_stress, or get_weekly_intensity_minutes, so the agent must infer the distinction.

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?

There is no explicit when-to-use or when-not-to-use guidance. The mention of getWeeklySteps is only a cross-reference for parameter validation, not a routing hint, and no alternative tool is named for related stress queries. The agent is left to infer that this is the weekly-aggregate counterpart to get_stress_data.

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