check_calendar_availability

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

No annotations exist, so the description carries full burden. It discloses that the tool returns 'Structured JSON with availability and conflicts or an error message', providing insight into the tool's behavior. It also lists parameters with format hints. However, it does not mention any side effects, though for a read-only check like this, that is acceptable. The transparency is good but not exhaustive.

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: a one-sentence summary followed by a brief list of arguments. Every sentence adds value, and the key purpose is front-loaded. There is no fluff or repetition, making it efficient for an agent to parse.

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?

The tool has 3 parameters, all described; an output schema is mentioned (though not shown); and the description explains return values. However, it lacks details such as whether checking applies to all calendars or just the specified one, timezone handling, or how conflicts are determined. For a simple checking tool, it is largely complete but has minor gaps.

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?

The input schema has 0% description coverage, meaning no parameter descriptions. The tool description compensates fully by explaining the format for 'start_datetime' ('YYYY-MM-DD HH:MM'), the unit for 'duration_minutes' (in minutes), and that 'calendar_name' is optional. This adds significant meaning beyond the raw schema types and defaults.

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 tool's purpose: 'Check whether a Calendar time slot conflicts with existing events.' It uses a specific verb ('check') and a well-defined resource ('Calendar time slot'). This purpose is distinct from sibling tools like 'create_calendar_event' or 'list_calendar_events', as it focuses on conflict detection rather than creation or listing.

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 implies the tool is used for checking availability, but does not explicitly provide guidance on when to use it versus alternatives (e.g., before creating an event). There is no mention of when not to use it or references to other tools. The usage is clear from context but lacks explicit direction.

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