Create Event

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

Annotations only declare it is a non-idempotent write; the description adds the genuinely non-obvious behavior: no duplicate detection, immediate insertion with an eventId, versus a deferred two-phase flow when the user's settings require Thunderbird's dialog, in which case existence is confirmed via listEvents with the reviewId. That is exactly the kind of context annotations cannot convey.

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?

Information is front-loaded and every sentence earns its place, with routing, duplicate-check advice and return behavior packed densely. The final clause ('listEvents with the reviewId of the result tells') is slightly convoluted and costs a little readability.

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 13-parameter mutation tool with no output schema, the description compensates by explaining that eventId (or a reviewId-based path) comes back and under what conditions. Permissions or calendar-writability caveats are left to the schema's calendarId note, a minor gap.

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 13 parameters (including skipReview, reminders, calendarId defaults and enum semantics) are already documented in structured data. The description only indirectly touches skipReview through the settings-versus-immediate-creation explanation, so the baseline 3 applies.

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 and resource ('Create a calendar event') and immediately distinguishes it from two siblings: updateEvent for changes and createTask for to-dos. An agent can tell exactly what this tool does and what it is not without opening the schema.

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 explicit routing rules: use updateEvent to modify, createTask for to-dos, and call listEvents first because no duplicate check is performed. These are concrete when-to-use and pre-requisite instructions rather than implied guidance.

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