check_calendar_availability

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

No annotations are provided, so the description carries full burden. It states the tool returns busy/free status and uses UTC timezone, which is good. However, it doesn't disclose details such as whether event names are returned, limitations on calendar types, or how it handles all-day events.

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 extremely concise: two sentences with no wasted words. It front-loads the core purpose and includes key usage context (UTC timezone) efficiently.

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?

Given the tool's simplicity (4 parameters, no nested objects, no output schema), the description is mostly complete. It explains inputs, defaults, timezone, and return type (busy/free). Could add more on exact output structure, but not required due to low complexity.

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%, setting baseline at 3. The description adds value by specifying default start and end times (09:00 and 17:00) and that all times are in UTC, which are not in the schema. This helps the agent understand parameter behavior.

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 clearly states the verb ('Check'), resource ('free/busy status of people's calendars'), and scope ('one or more people, specific date and time range'). It distinguishes itself from siblings: 'create_calendar_event' (creating events) and 'find_meeting_times' (finding meeting times) are different tools.

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 description mentions that all times are in UTC and provides default times, but it doesn't explicitly state when to use this tool versus alternatives (e.g., 'find_meeting_times') nor when not to use it. Usage is implied but lacks explicit guidance.

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