List WhatsApp groups

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so the safety profile is covered. The description adds genuine value beyond that by disclosing the return shape (JID format ending in @g.us plus name), which is not in any structured field since there's no output schema. 'Read-only' simply restates the annotation and earns no credit.

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, zero waste, with the core behavior and return shape front-loaded before the usage hint. Nothing could be cut without losing information.

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 zero-required-parameter read tool with full annotation coverage, the description is essentially sufficient: it says what comes back and why you'd call it. It stops short of noting result volume or whether group listings are paginated, but no pagination parameter exists, so the gap is minor.

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 description coverage is 100% and the lone parameter instance_id is fully documented in the schema, including the ZAPZAP_INSTANCE_ID fallback and the list_instances prerequisite. The description adds nothing about the parameter, so the baseline 3 applies.

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 and resource ('Lists the WhatsApp groups the instance belongs to') and immediately specifies the return payload (JID ending in @g.us, plus name). This clearly distinguishes it from the singular get_group_info and from create_group/manage_group_participants siblings.

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 says when to reach for it: 'Use to find a group JID to send to or manage.' That routes the agent to the right workflow, though it doesn't name an alternative (e.g., get_group_info) or state when-not to use it.

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