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

Annotations already declare readOnlyHint=false, idempotentHint=false and openWorldHint=true, so the bar is lower. The description adds genuinely useful context beyond those flags: generating a new link revokes the previous one, which is a real side effect an agent should anticipate and is not obvious from destructiveHint=false. It stops short of covering rate limits or permission 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?

A single front-loaded sentence with zero filler; the parenthetical about revocation is the one clause that earns its extra length.

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 simple 3-parameter mutation with annotations covering the safety profile, the core is adequate. With no output schema, the description could have stated what is returned (the link string) and its format, and it leaves group_id entirely undocumented alongside the schema – enough gaps to keep it at minimum-viable.

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 67% (profile_id and phone_number_id are documented; group_id is not), which sits between the low and high baselines. The description adds no parameter-level meaning beyond the schema, so it neither compensates for the undocumented group_id nor improves on what is already there.

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 ('Generate a fresh invite link for a WhatsApp group') and adds the key side effect parenthetically. An agent can immediately distinguish this from whatsapp_group_create, whatsapp_group_get, and whatsapp_group_update in the sibling set.

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?

Usage is implied by the purpose, and there is no alternative invite-link tool in the sibling list to redirect to, so no explicit routing is required. However, it offers no prerequisites (e.g., admin rights needed) and no when-not-to-use caution, so guidance stays at the implied level.

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