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

Annotations already declare readOnlyHint=false, destructiveHint=true, openWorldHint=true, and idempotentHint=false, so the safety profile is covered. The description adds a genuine behavioral fact not in the annotations: the sign-in and Aisle membership requirement needed to invoke it successfully. It stops short of explaining what the destructive hint means in practice (no delete/undo semantics on the created event).

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, no filler, and the core action and its field list are front-loaded ahead of the prerequisites. Every clause carries information.

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 9-parameter, non-idempotent mutation with no output schema, the description covers the action, the populated fields, and the auth gate, which is enough to call it correctly alongside a fully documented schema. It leaves the conditional wedding_id requirement and the ISO date format to the schema, which is acceptable given 100% coverage.

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 all nine parameters are self-documenting; the baseline is 3. The description lists the same field set as the schema without adding format rules (ISO for date/end_time), enum constraints for type, or the conditional rule for wedding_id exposed in 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?

States a specific verb+resource ('Creates an event in the selected wedding') and enumerates the fields it populates (name, type, date, time, venue, dress code, description). An agent can distinguish it from add_my_accommodation, add_my_guest, and especially update_my_event, whose write semantics are modifying rather than creating.

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 prerequisites ('Requires sign-in and an Aisle membership') and scopes the target to 'the selected wedding', which is real guidance. However it never states when to use this versus update_my_event, nor when to supply wedding_id explicitly beyond what the schema already says. Usage is implied rather than spelled out.

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