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

Annotations already mark this as a non-readOnly, non-idempotent, non-destructive mutation, so the safety profile is partly covered. The description adds real behavioral context beyond that: only named days change, split shifts are expressed as two entries, and closed: true closes a day. It does not say what happens to existing entries on a named day.

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, each earning its place: the operation and partial-update scope first, then split shifts and closure, then time format. No filler and well front-loaded.

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 one-parameter mutation tool with no output schema, the description covers the nested structure, the partial-update semantics, and time syntax — enough to call it correctly. Only the exact day-name format and the response/confirmation behavior are unaddressed.

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 0% and the single parameter is a nested array of day objects, so the description carries the burden — and it does: it explains the day field, open/close time strings with concrete examples ("9am", "6:30pm"), the closed boolean, and repeated entries for split shifts. It leaves the accepted day-name vocabulary unspecified.

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 and resource — setting the owner's weekly working hours for named days — which is clear on first read. It does not, however, distinguish itself from close siblings like propose_regular_hours, propose_holiday_hours, or update_calendar_settings, so an agent cannot route between them without inference.

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?

It usefully scopes the write by stating that days not named are left untouched, which implies when a partial edit is appropriate. But there is no explicit when-to-use versus propose_regular_hours or update_calendar_settings, and no stated prerequisites or permissions.

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