gcal_find_free_slots

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

Annotations already mark this as read-only and non-destructive, and the description adds meaningful behavior: it returns all slots with at least the requested duration and describes the JSON array output with start/end ISO datetimes. It also clarifies that earliest/latest hours constrain slot start/end boundaries.

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?

The description is front-loaded with the core purpose and use case, then gives a structured Args/Returns breakdown. The Args list repeats some schema information, but it is organized and compact enough to scan quickly.

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 scheduling tool with five parameters, the description covers inputs, output format, and slot semantics. It does not discuss timezone handling, working-hours assumptions, or why a slot might be considered unavailable, but those are not essential for basic invocation.

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?

Despite the reported 0% schema coverage, the description's Args section documents each parameter, including boundary semantics for earliest_hour and latest_hour and the role of calendar_id. It mostly mirrors the schema metadata, but it adds explicit 'don't suggest before/after' wording that helps an agent call the tool correctly.

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 opens with a specific verb and object — find available time slots — and states the two central constraints (duration, date). It also clarifies the result semantics: all slots with at least the requested duration, which distinguishes this from gcal_get_events or schedule_find_conflicts.

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 explicitly identifies scheduling work blocks, appointments, or time-bound tasks as the context, which is clear guidance for when to use it. However, it does not name sibling alternatives or state when not to use it, so it stops short of full routing guidance.

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