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

Annotations already mark readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds valuable behavioral context: @lid identifiers are explained as a privacy feature, and the warning about using the unofficial Wacli client and possible ToS restrictions goes beyond structured data.

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?

Purpose is front-loaded, and each sentence adds useful information including return fields, @lid handling, and client warnings. Slightly longer than necessary, but the extra detail is meaningful rather than 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?

Given the simple input schema, existing output schema, and read-only annotations, the description is largely complete: it covers unusual @lid identifiers, return contents, and a significant risk warning. Minor gaps remain around sorting or empty-result behavior, but these are not critical for invoking the tool correctly.

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?

Input schema provides 100% description coverage for the single 'limit' parameter, so the description does not need to compensate. It adds no additional parameter-level detail, keeping this at the baseline score.

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?

Description begins with specific verb and resource: 'Lists WhatsApp conversations with last message preview.' It clearly states return fields (chat IDs, contact names, message snippets), which distinguishes it from related tools like whatsapp_read_messages or whatsapp_list_groups.

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 implies use for getting an overview of WhatsApp chats and provides follow-up guidance ('use the Name field for display and the JID/chat_id for subsequent calls'), but it does not explicitly state when to choose this over alternatives such as whatsapp_search_contacts or whatsapp_read_messages.

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