calendar_list_instances

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

The description discloses important behavioral details: it uses Google occurrence IDs and originalStartTime, and it never synthesizes IDs or splits a series. This goes beyond the annotations by explaining internal mechanics and constraints. It does not contradict the readOnlyHint or destructiveHint annotations. It does not mention pagination or error behavior, but the disclosed information is substantial.

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 concise, consisting of two sentences that directly address the tool's function and one key behavioral constraint. There is no excessive verbosity or redundant information. The structure is clear and efficient.

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 description lacks essential context such as return format, pagination behavior, how deleted instances are handled (though showDeleted exists as a parameter), and how this tool differs specifically from calendar_list_events. Given the complexity of listing recurring instances, the description is incomplete for an agent to fully understand the tool's output and edge cases.

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 description provides no explanation of any of the 8 parameters. While 'explicit time bounds' hints at timeMin and timeMax, it does not map parameters to their purposes, defaults, or requirements. With 0% schema description coverage, the description fails to add value for parameter understanding.

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 expands a recurring master event into its instances within explicit time bounds. The verb 'expand' is somewhat unusual but the context makes the purpose understandable. It does not explicitly differentiate from the sibling tool calendar_list_events, but the mention of 'recurring master' and the tool name provide some distinction.

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 does not provide explicit guidance on when to use this tool versus alternatives like calendar_list_events or calendar_get_event. It does not state preconditions, typical scenarios, or conditions that would favor this tool. The only guideline is implicit through the mention of 'recurring master,' but no explicit usage instruction is given.

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