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

With no annotations, the description carries the burden well: it discloses the external side effect that guests are notified, a hard operational restriction for agent-initiated turns, and the length-preserving behavior when only start is supplied. It omits whether the guest restriction raises an error or is silently skipped, and says nothing about the response.

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?

Two sentences, dense and front-loaded with the verb and resource; identifier provenance arrives before the behavioral constraints. The final clause about Caddie's own turn is convoluted and slightly opaque, costing a point on structure.

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 7-parameter mutation tool with zero annotation and zero schema-description coverage and no output schema, the description covers every parameter at least implicitly plus the key side effect and restriction. An agent could call this correctly from the description alone.

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 0%, so the description must compensate, and it largely does: id/calendar_id/account_id provenance, start/end as ISO date-times with offset, minutes as an alternative to end, and 'rename' implying title. Remaining gaps are format detail (offset requirement, timezone default) and the exact role of calendar_id in 'move'.

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?

States a specific verb pair and resource: 'Rename or move a Google Calendar event'. This cleanly separates it from create_event, delete_event, and list_events among the siblings, and it even names list_events as the source of the identifiers.

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?

Gives concrete preconditions ('id, calendar_id and account_id from list_events') and an explicit usage restriction: from an agent's own turn only events without guests are changed. It does not explicitly contrast with create_event/delete_event, but those distinctions are self-evident from the verb.

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