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

Annotations already declare readOnlyHint=true and openWorldHint=false, and the description goes well beyond them: without an output schema it defines each return field, explains the derived boolean (ready = connected && loggedIn), and states the operational precondition for subsequent actions.

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?

Front-loaded purpose sentence, then a tight bullet list of return fields, then the usage rule. Every line earns its place and nothing is repeated from the annotations.

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?

No output schema exists, yet the description fully documents the return payload and its semantics, and it supplies the readiness precondition an agent needs before calling send/write siblings. Nothing material is missing.

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?

Zero parameters, so the baseline 4 applies; there is no parameter ambiguity to resolve and the description correctly spends no words on arguments.

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?

Specific verb+resource: 'Check the connection status of the WhatsApp session.' It is clearly distinct from siblings like get_pairing_qr, restart_session, and unlink_whatsapp, and the returned field list makes the resource boundary 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?

Explicit when-to-use ('when a send or read fails, or when unsure whether WhatsApp is linked') plus a hard gating rule ('only send or read when ready is true') that routes the agent away from prematurely calling send_message/read_chat_history.

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