find_free_time

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

readOnlyHint already tells the agent this is a safe read, and the description adds real behavioral content beyond that: free/transparent events and cancelled events do not block time. Still silent on whether free windows are split per day, whether working_hours defaults apply, and timezone resolution beyond what the schema says.

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?

Two sentences, zero filler, with the core capability front-loaded and the blocking rule immediately after. Nothing could be cut without losing 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 read-only availability query with well-documented date inputs, the definition covers purpose, the key constraint, and the blocking semantics. No output schema exists, but the natural return (windows of >= duration_minutes) is self-evident from the description. Minor gaps around per-day splitting don't make it incomplete for a 6-param query tool.

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?

At 50% schema coverage, the description must compensate. It explains duration_minutes (minimum window length) and hints at calendars ('all (or selected)'), but the 'accounts' parameter and 'working_hours' object are untouched by the description, leaving two parameters documented only thinly or not at all.

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+resource ('Free time windows ... across all (or selected) calendars') with a quantified constraint. Among siblings, which are all event CRUD/listing tools, this is unmistakably the availability-computation tool, so no confusion is possible without opening a schema.

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 parenthetical '(or selected) calendars' and the mention of duration_minutes imply the intended scenario (find a slot of a given length), but there is no explicit when-to-use, no prerequisite statement (e.g. calendars must be connected), and no comparison to list_events/search_events.

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