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

Annotations already include readOnlyHint, openWorldHint, and idempotentHint. The description adds that the tool returns specific fields, that a one-time Facebook login is required and cannot be done by the agent, and that subsequent token exchange/number registration is automatic. This provides actionable behavioral context beyond the hints.

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 only three sentences. It front-loads the purpose and return value, then adds the critical user-requirement and the 'connected already true' no-action branch. Every sentence earns its place with no redundancy.

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?

With no parameters and no output schema, the description carries the burden of explaining the return values. It lists the fields and explicitly instructs the agent to surface connect_url and ask the user to finish login, and covers the connected-true branch. It is complete for correct invocation, though it does not elaborate on meanings of 'configured' and 'phone_number', which is a minor gap.

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?

The tool has zero parameters, so schema coverage is trivially 100%. Per the baseline rule, a 0-parameter tool earns a 4; the description does not need to compensate for any undocumented parameters.

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 a specific verb ('Get the link') and resource ('WhatsApp connect link'), and explains the purpose (so broadcasts reach real phones). It can be distinguished from siblings like connect_whatsapp and whatsapp_status without opening their schemas.

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 clear context: the link is for the user to complete a Meta-required Facebook login, and if connected is already true no action is needed. However, it does not explicitly name or compare with the sibling connect_whatsapp, so it lacks full alternative routing beyond the connected condition.

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