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

Annotations already declare readOnlyHint=false, destructiveHint=false and idempotentHint=false, so the bar is lower; the description still adds real value by clarifying that nothing existing is modified and nobody is notified, plus the POST endpoint. It stops short of stating idempotency/retry behavior or auth requirements.

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 compact, front-loaded segments — operation class, effect/scope, required input, endpoint — with no filler. Every clause adds distinct 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 create tool with no output schema, the description covers the operation's effect and required input well, and the schema carries the parameter detail. It could still hint at what is returned (e.g. a new calendar id) since no output schema exists, but nothing essential is missing.

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% and all 9 parameters are documented in the schema, so the baseline is 3. The description only adds 'Needs a title', which the schema's required list already conveys; none of the other eight parameters (timezone, templates, custom_data) are elaborated on.

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 a new calendar in the AddEvent account') and immediately scopes it ('a new, empty calendar'), which cleanly separates it from addevent_create_event and addevent_update_calendar. The 'WRITE:' prefix signals the operation class up front.

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 implied usage context ('a new, empty calendar; nothing existing is changed') and a required precondition ('Needs a title'), but never names an alternative or an exclusion, e.g. to modify an existing calendar use addevent_update_calendar. Usage is inferable but not explicit.

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