List instances of a recurring event

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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior, so the description adds complementary behavioral detail rather than repeating it. It discloses that exceptions already made to the series show changed times, that show_deleted includes cancelled occurrences, and that unbounded infinite series require pagination via page_token — all useful traits beyond the structured annotations.

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 dense but efficient: purpose first, then instance-id usage, exception behavior, deleted handling, and pagination. Every sentence contributes distinct information and no content is wasted or redundant with the schema.

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 no output schema, the description still conveys the key return concept (individual ids plus concrete start/end) and covers the operational requirements: correct master id, optional window, deleted-instance flag, and page_token for unbounded series. An agent has enough to call this tool correctly and understand its pagination and filtering behavior.

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 coverage is 100%, so the baseline is 3, but the description raises the value by linking event_id to the recurring series master, explaining the instance id convention, and clarifying how time_min/time_max bound the expansion window. It adds meaning beyond the raw parameter descriptions without needing to restate every field.

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 states a specific verb ('Expands') and a precise resource: one recurring event series master turned into individual instances with unique ids and concrete start/end times. This clearly separates it from list_events and get_event, and the example id format removes ambiguity about what an 'instance' is.

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 gives practical guidance: use an instance id with update_event or delete_event for single-occurrence changes, include show_deleted for cancelled instances, and bound the window with time_min/time_max. It does not explicitly state when to prefer this over list_events, but the 'series master id' framing and cross-tool usage instructions make the intended context clear.

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