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

Annotations already declare readOnlyHint=false, idempotentHint=false and openWorldHint=true, so the description earns credit for adding what they don't: the created event becomes visible to all users with schedule access, and Schedule It may fire notifications to linked resources under the account's own settings. Both are real side effects beyond the structured hints. It stops short of describing failure behavior, permission requirements, or what the call returns.

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?

Three tight sentences plus the endpoint, front-loaded with the WRITE marker and the resource, then side effects, then the pre-call caution. Every clause carries information; nothing is redundant with the title or 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?

For a 10-parameter create tool with a nested custom_fields object, the description supplies the operation's meaning and side effects, and the schema carries the parameter burden. The remaining gap is the return value: with no output schema, the description never says whether the new event (or its id) is returned, which the agent needs to chain into a follow-up get or update.

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%, so the baseline is 3 and the schema already documents all ten parameters including the REPLACES-or-clear semantics for resource_ids, notes and custom_fields. The description only gestures at 'title, dates and resources' as the fields to confirm, adding no format or syntax information beyond the schema.

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 opens with a specific verb and resource ('WRITE: create a new event') and enumerates the domain shapes (booking, shift, job, task), so the agent knows exactly what object is produced. Because every sibling operates on a different resource (group, resource, get/list/update/delete), the create-a-new-event framing is unambiguous without needing to name a sibling.

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?

It gives an explicit pre-call instruction ('Confirm the title, dates and resources with the user first') and states the outcome of a successful call (visible to everyone with schedule access), which tells the agent the stakes of the operation. It doesn't explicitly contrast with scheduleit_update_event or state when-not to use this, so it falls short of the full when/alternatives treatment.

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