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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered by structured data. The description adds useful behavioral content by disclosing the returned dimensions, but says nothing about pagination, permissions, or formatting. Given annotation coverage, a 3 is appropriate.

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?

A single dense sentence with the range constraint front-loaded and zero filler. It is compact and information-dense, though the fragmentary style slightly reduces immediate parseability.

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?

With no output schema, the enumeration of returned metrics ('goal share, hard share, area balance, overrides, streak, milestone pace') usefully compensates by telling the agent what it will get back. Combined with the fully documented single parameter and complete annotations, it is nearly complete; it only lacks explicit routing versus summarize_day.

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 the single 'date' parameter is already documented ('any day of the week, default today'). The description reinforces the week range and partial-week behavior for the current week, but adds no syntax beyond the schema, so 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?

The description is a noun-phrase content enumeration ('main-step days, goal share, hard share...') rather than a verb+resource statement; the action ('summarize') is carried only by the title/name. It is specific about what the week summary contains and implicitly contrasts with the day granularity via 'Monday to Sunday', but it never states the operation outright or names the summarize_day sibling.

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 when-to-use guidance, no exclusion conditions, and no reference to the obvious alternative summarize_day. The weekly framing ('Monday to Sunday') implies the context, but the agent must infer it.

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