join_group_with_link

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

The description discloses behavioral traits beyond annotations: it explains the system message, the new chat for the paired user, and reversibility via leave_group. Annotations indicate a write operation (readOnlyHint=false) and non-destructive, which align. It adds value without contradiction.

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 two sentences, front-loading the purpose and then adding relevant behavioral and reversibility details. Every sentence earns its place with no wasted words.

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 tool with 1 parameter, the description explains input format, behavioral effects, reversibility, and return type ({jid}). It also references a sibling tool, making it contextually complete despite lacking an output schema.

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?

With 100% schema coverage, the baseline is 3. The description adds a useful format example ('https://chat.whatsapp.com/') and clarifies that either the full URL or bare code is accepted, providing slight extra meaning over the schema's description.

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 clearly states the tool's purpose: 'Join a WhatsApp group via a `chat.whatsapp.com/` invite URL or the bare invite code.' It uses a specific verb and resource, and distinguishes from sibling tools like create_group and get_group_invite_link.

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 description provides clear context about the outcome (system message, new chat appearance) and mentions reversibility via leave_group. It doesn't explicitly state when not to use it, but it does reference a related tool (get_group_invite_link) for comparison.

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