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

Beyond the annotations (which only flag it as a non-read-only, destructive write in a closed world) it discloses the approval/pending state, that owners get a notification, that approved time lowers capacity in Workload for Mon–Fri weeks touched, the 366-day cap, and that the note is refused when the time off is for somebody else. That is substantial side-effect and authorization context an agent could not infer from structured fields.

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?

Front-loaded with actor and resource before the conditional rules, and every clause carries information (kinds, span, capacity effect, approval logic, note ownership). It is a single dense paragraph of long semicolon-joined sentences, which is harder to parse than it needs to be, but nothing is 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 mutating, multi-actor tool with no output schema, the description covers the outcomes an agent must anticipate: resulting approval status, notification side effect, capacity change, span limit, and the note-permission failure mode. Nothing material for correct invocation is missing.

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 already 100%, so the baseline is 3, and the description adds real semantics on top: the note is private to the subject and refused when recording for another person, and a single day applies when no last day is given. It does not add detail on minutesPerDay or userId beyond what the schema already says.

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 and resource (records time off), the two actors it can act on (the user, or on Pro an editor of a project the user owns), and the accepted kinds and date span. It is clearly distinguishable from siblings like approve_time_off, update_time_off, list_time_off and remove_time_off.

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 explicit conditions: own time off becomes a pending request when an owner of an edited project plans with the team calendar, otherwise approved at once, while time off for an editor is approved immediately. It also states constraints (366-day maximum, note only writable by the subject) but does not name the sibling to use when correcting or cancelling an existing entry.

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