whatsapp_join_group_with_invite

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

Annotations already cover the safety profile (destructiveHint=false, readOnlyHint=false, idempotentHint=false). The description adds a genuinely new behavioral fact: 'Other participants see this number join.' That is real side-effect disclosure. However it omits error cases (expired code, invalid inviter) and confirmation detail, so a 3 is warranted.

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 tight sentences, front-loaded with the scope distinction and no wasted words. The mention of 'Returns a success confirmation' is slightly redundant but harmless.

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?

Covers purpose, mechanism distinction, and the visible side effect. But with no output schema, the description does little to explain the return beyond 'a success confirmation', and error/expiry behavior for a join operation is not addressed.

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%, so all four parameters are documented in the schema itself. The description adds only that the code/groupId/inviterId come from a received invite message, with no syntax or format detail beyond the schema. Baseline 3 is correct.

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 ('Accept a group invite') and crucially distinguishes the mechanism: 'received as a direct message (not a link)'. This differentiates it from the sibling whatsapp_join_group_with_link, though it doesn't name that sibling explicitly.

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 '(not a link)' parenthetical implies when to use this over the link-based sibling, and the description says to use 'the fields from that invite message'. But it never explicitly names whatsapp_join_group_with_link or states exclusions outright, leaving routing partly to inference.

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