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

Annotations already declare readOnlyHint=false, destructiveHint=false and openWorldHint=true, so the safety profile is covered. However the description never says whether this is a partial patch (unmentioned fields preserved) or a full replace, what happens to invalid dates, or whether rename/move is the full extent of mutation — meaningful gaps for an edit tool. It does not contradict the annotations (an edit is non-destructive), but it adds little operational detail.

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 short sentence with the action front-loaded and zero filler. It is efficient, though the brevity here reflects under-specification rather than tightly packed information.

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 4-parameter mutation tool with no output schema and half the parameters undocumented in the schema, the description should explain partial-update behavior and the is_recurring flag. Instead it covers roughly two of the four editable facets and says nothing about the result of the call.

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 only 50%: date and holidayId are documented inline, while name and is_recurring are bare types. The description maps "renames" to name and "moves" to date, which partially compensates, but it is entirely silent on is_recurring, leaving one undocumented parameter with no semantics anywhere.

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 pair (renames or moves) applied to a specific resource (a day off), so the agent knows this is an edit operation on an existing record. It implies a distinction from create_holiday/list_holidays, though it never names them explicitly, and it omits one editable facet (recurrence) that the schema exposes.

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?

"the trainer added" narrows the scope to holidays the caller owns, which is implicit but useful eligibility context. Beyond that there is no explicit when-to-use guidance, no mention of the list_holidays → update_holiday flow beyond the schema's holidayId note, and no statement about when to create a new day off instead.

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