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

Annotations already indicate readOnlyHint=true and idempotentHint=true, so no safety concerns need to be added. The description adds useful behaviors such as default limit of 50 and substring matching for query, which go beyond annotations. However, it does not explain what happens on missing JID, pagination behavior beyond the limit, or the relationship between the two listed actions and the flattened action note, leaving gaps in behavioral understanding.

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 brief and front-loaded with the core purpose, followed by concise action definitions. However, the cryptic '[Flattened action: get]' note is unclear and disrupts the flow, introducing confusion rather than clarity. Minimal waste otherwise.

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?

The tool has no output schema, so the description should describe return values, but it only vaguely mentions 'full contact info' for get. It lacks details on list response structure, error conditions, pagination, and the meaning of `account`. The flattened action note and the existence of a dedicated list tool are not reconciled. Overall, the description is insufficient for an agent to reliably select and invoke the tool in various scenarios.

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?

Since schema description coverage is 0%, the description must explain parameters. It does clarify `query` (substring on name/phone), `limit` (default 50), and `jid` (used for get). However, it fails to explain the `account` parameter and does not clearly state how parameters select between list and get actions. The '[Flattened action: get]' note implies jid is used, but the list action also needs query/limit, leaving the parameter-action mapping ambiguous.

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 reads WhatsApp contacts and lists two primary actions (list and get). However, it does not distinguish itself from the sibling tool `whatsapp_contacts_list`, which presumably performs the same list operation, creating ambiguity about the tool's unique purpose. The flattened action note further muddies the intended operation.

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 mentions that list and get are available but provides no guidance on when to use this tool versus the closely named `whatsapp_contacts_list`. It also fails to explain when each action should be chosen (e.g., get when you have a JID, list for search), and the flattened action note suggests only get may be active, without clarifying how to invoke the list functionality.

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