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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safe-read profile is clear. The description goes further by disclosing non-paginated single-response behavior, split into upcoming/past, newest-first ordering, and the differing field sets for each category. This is rich behavioral context that the annotations do not provide.

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?

The description is front-loaded with the primary usage, followed by a compact breakdown of return structure and field details, and ends with explicit routing to sibling tools. Every sentence contributes a distinct, necessary piece of information; there is no filler.

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 zero-parameter tool with an output schema, the description fully covers what an agent needs: what triggers the call, what comes back, how it's organized, and where to go for deeper detail. The absence of pagination is called out, and the field-level differences between upcoming and past items are specified. Nothing is left to inference.

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?

The tool has zero parameters, and the schema coverage is 100% (vacuously). Per the baseline for 0-param tools, a 4 is appropriate since description adds nothing about parameters, but nothing is needed. It does mention what the returned data contains, which indirectly aids understanding of what can be used.

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 states a specific verb and resource ('find or pick... Lemonvite invitations') and precisely scopes the result set ('every event the connected account created or co-hosts'). It explicitly differentiates itself from lemonvite_get_invitation and lemonvite_list_guests, leaving no ambiguity about which tool to choose.

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 opens with the exact trigger condition ('when the user wants to find or pick one of their Lemonvite invitations, or when you need the event_id...') and then names the alternatives for full details and guests. This gives an agent explicit when-to-use and when-to-use-other guidance.

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