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

Goes well beyond the readOnlyHint/destructiveHint/openWorldHint annotations: discloses a 500-record cap, result ordering, Pro plan gating, visibility limits (the person's own note only appears for the user's own time off), the semantic effect of 'approved' (lowers capacity), the approval workflow and who decides, and a data-quality caveat that names and notes are human-typed.

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-loads the essential scope and ordering in the first clause, and the long field enumeration earns its place because no output schema exists. It is still a single run-on sentence mixing return-field inventory with filtering, which makes it harder to scan than it needs to be.

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 description compensates fully by enumerating every returned field (person, kind, first/last day, minutes off per day with null meaning full working day, day count, status, decision metadata, approvability). Combined with the visibility and plan constraints, nothing essential 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 description coverage is 100%, so the schema already documents all four parameters. The description restates the same semantics (overlap on a day range, person filter scoped to self or editors, status filter) without adding new syntax, defaults, or edge-case behavior, 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?

States a specific verb and resource ('Lists time off (vacation, sick leave, other)') plus ordering ('soonest first') and a cap ('up to 500'). The scope sentence distinguishes it clearly from list_time_entries, list_timesheets and list_holidays by being about time-off records and their approval state.

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?

Scope rules (own time off plus, on Pro, editors of the user's projects; optional filters by person, status, or overlapping date range) imply when the tool applies. However, no sibling is named — an agent gets no explicit guidance on when to prefer list_timesheets or list_time_entries instead, or when to chain into approve_time_off/reject_time_off.

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