WhatsApp Business MCP

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

With no annotations provided, the description carries the full burden and excels by disclosing: sequential sending behavior ('one API call per recipient'), granular tracking ('Each result is tracked individually'), return structure ('JSON with per-recipient results'), and prerequisite state ('approved template').

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 uses a structured Args/Returns format that efficiently packs information without redundancy. Every sentence serves a purpose, though the structured format slightly reduces prose flow compared to integrated narrative.

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?

For a 4-parameter bulk operation tool with an output schema, the description is comprehensive. It covers all parameters, explains the sequential execution model, and describes the return format sufficiently, given that the output schema handles detailed return value documentation.

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?

Given 0% schema description coverage, the Args section compensates effectively by adding crucial constraints: country code requirement for phone numbers, default language value ('en'), and the critical constraint that components are 'same for all recipients.' Deducts one point for lack of detail on what 'components' actually contain structurally.

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 explicitly states 'Send an approved template message to multiple phone numbers,' providing a specific verb (send), resource (template message), and scope (multiple phone numbers). This clearly distinguishes the tool from the sibling send_template_message (single recipient) and links to template management siblings via the 'approved' qualifier.

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 usage context through 'approved template' (suggesting prerequisite validation) and 'multiple phone numbers' (suggesting bulk use), but lacks explicit guidance on when to choose this over send_template_message or warnings about rate limits despite noting sequential API calls.

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