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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds meaningful context with '(live)' indicating real-time data and explicitly enumerates the returned participant attributes, going beyond the structured annotations.

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?

Two tight, front-loaded sentences convey action, output shape, and input origin without redundancy. Every clause earns its place, and there is no filler or repetition of annotation metadata.

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 read-only listing tool, the description covers input semantics, live behavior, and return fields sufficiently well, especially given strong annotations. The main gap is the undocumented 'account' parameter, which prevents a perfect completeness score.

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 0% schema description coverage, the description must compensate for both parameters. It does explain group_jid well (format and source), but the 'account' parameter is entirely undocumented, leaving agents to guess its purpose or required values.

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 uses a specific verb ('List') and resource ('members of a WhatsApp group'), clearly distinguishing it from mutation siblings like whatsapp_group_participants_add/remove. It also specifies the return fields (JID, phone, admin flag), making the tool's purpose concrete and unambiguous.

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 useful context: it requires group_jid in the format '…@g.us' sourced from whatsapp_groups. However, it does not explicitly state when to choose this tool over alternatives like whatsapp_chat_metadata or whatsapp_group_manage_update, nor does it mention exclusions.

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