wa_send_text_message

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

With no annotations, the description carries the full burden of behavioral disclosure. It discloses the critical 24-hour window limitation and the need to use templates outside that window. However, it does not mention potential costs, authorization requirements, or message delivery/error behavior, which prevents a perfect score.

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 well-structured: a one-sentence purpose, a clearly highlighted NOTE about the 24-hour window, and a compact Args section. Every sentence adds necessary value with no 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?

Despite the helpful 24-hour context, the description is incomplete for a 5-parameter tool with no annotations and no output schema. It fails to document the required 'phone_number_id' and 'text' parameters, the 'confirm' flag semantics, or any return value/error information.

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?

Schema description coverage is 0%, so the description must compensate. It only explains the 'to' parameter with formatting guidance. It completely omits 'text', 'phone_number_id', 'confirm', and 'preview_url', leaving required parameters like 'phone_number_id' unexplained and 'confirm' 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 uses a specific verb and resource: 'Send a free-form text message to a WhatsApp number.' It clearly distinguishes itself from sibling tools like wa_send_template_message and wa_send_image_message by emphasizing 'free-form text message.'

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 explicitly states when the tool is appropriate: only within the 24-hour customer service window after the user messages you. It also names the alternative path ('use a template') outside that window, giving clear when-to-use and when-not-to-use guidance.

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