WhatsApp MCP for macOS

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

Annotations already declare readOnlyHint=true and destructiveHint=false, indicating a safe read operation. The description adds valuable behavioral context beyond annotations: it specifies that partial matching is supported and describes the return format (JID, display name, phone number). However, it doesn't mention rate limits or authentication requirements, leaving some behavioral aspects uncovered.

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 efficiently structured with a purpose statement, return value explanation, usage guideline, and parameter details in four concise sentences. Every sentence adds value without redundancy, and key information is front-loaded for quick comprehension.

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?

Given the tool's simplicity (1 parameter, read-only operation), the description is complete: it covers purpose, usage, return values, and parameter semantics. With an output schema present, the description appropriately focuses on context rather than return value details, making it fully adequate for agent decision-making.

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?

With 0% schema description coverage, the description fully compensates by explaining the 'query' parameter's purpose ('Name or phone number to search for') and behavior ('partial match supported'). This adds essential meaning beyond the bare schema, though it doesn't detail format constraints like phone number patterns.

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's purpose with a specific verb ('Search') and resource ('WhatsApp contacts'), and distinguishes it from siblings like 'whatsapp_search_messages' by focusing on contacts rather than messages. It explicitly mentions searching by name or phone number, providing clear differentiation.

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 to use this tool: 'Use this to find a contact before reading their messages or sending them a message.' This provides clear guidance on its purpose relative to siblings like 'whatsapp_get_messages' and 'whatsapp_send', making it easy for an agent to choose this tool appropriately.

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