whatsapp_join_group_with_link

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

Goes beyond the annotations by disclosing a real side effect visible to others ('Other participants see this number join') and the return value (joined group JID). Annotations already cover the safety profile (readOnly=false, idempotent=false), so the added social-visibility warning is meaningful extra context.

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 short sentences, front-loaded with the action, then the side effect, then the alternative route, then the return value. 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 single-parameter mutation with annotations covering safety and no output schema, the description covers purpose, input format, side effect, alternative, and return value. Nothing an agent needs to call it correctly 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 coverage is 100%, so the baseline is 3, but the description adds the concrete link format (chat.whatsapp.com/<code>) that tells the agent the code is the trailing path segment rather than the whole URL, which the schema's terse 'Invite link code' does not.

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 (join) and resource (group) via a named input form, and the parenthetical 'chat.whatsapp.com/<code>' pins down exactly which input shape this tool takes, distinguishing it from the sibling whatsapp_join_group_with_invite.

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?

Explicitly names the alternative workflow ('To preview the group first, use whatsapp_get_group_info_from_link'), giving a clear when-to-use-this-first context. It does not state exclusions or differentiate from whatsapp_join_group_with_invite explicitly, so it stops short of a 5.

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