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

Annotations indicate readOnlyHint=false, destructiveHint=false, idempotentHint=false, which are not contradicted. The description adds the admin requirement and the action semantics, but doesn't disclose potential side effects like rate limits or whether actions are reversible. It's adequate but not rich.

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 concise and front-loaded with the purpose. The '[Flattened action: promote]' suffix is a bit cryptic but doesn't waste space. It's efficient.

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?

Given the tool has 3 params, no output schema, and no annotations beyond basic hints, the description covers the main actions and input format. However, it doesn't explain the 'account' parameter or the exact format of group_jid, and the '[Flattened action: promote]' is unclear. It's adequate for a simple tool but leaves some gaps.

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 0%, so the description must compensate. It explains 'users' (phone numbers or JIDs) and 'action' (though action is not in the schema properties, it's mentioned in the description). It doesn't explain 'group_jid' or 'account' beyond their names, but the description's mention of group admin and users provides some context. Baseline 3 is appropriate.

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 manages WhatsApp group participants and lists the four actions (remove, promote, demote, add) with their effects. It distinguishes from siblings by naming the specific actions, though the tool name already implies 'promote'.

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?

It provides clear context: the connected account must be a group admin, and it specifies the input format (1-50 phone numbers in E164 or JIDs). It doesn't explicitly say when to use this vs. the sibling tools like whatsapp_group_participants_add or demote, but the action parameter covers that.

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