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

Annotations already declare destructiveHint=true, idempotentHint=false, and openWorldHint=true, so the safety profile is covered structurally, but the description adds nothing: it does not say whether the action is irreversible, whether the caller's own membership is removed, or whether admin/instance state affects the outcome.

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?

One short phrase, front-loaded and free of waste, but the brevity reflects under-specification rather than tight authoring; it conveys no more than the tool name.

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?

The schema and annotations are rich enough for the agent to construct the call, but for a destructive, non-idempotent group mutation the description should at minimum state irreversibility and who is removed. That guidance is absent.

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 coverage is 100% — group_id format (120363XXX@g.us) and instance_id are fully documented in the schema, so the baseline of 3 applies. The description contributes no additional meaning about either parameter.

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?

"Leave a WhatsApp group" restates the tool name almost word for word; it names the verb and resource but adds no scope, no effect, and no differentiation from siblings like whatsapp_remove_group_participant or whatsapp_get_group_data.

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?

There is no statement of when to use this tool versus alternatives such as whatsapp_remove_group_participant (removing someone else) or whatsapp_create_group, and no prerequisites are mentioned. The agent must infer all routing from the name alone.

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