WhatsApp MCP Server

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

No annotations are provided, so the description carries the full burden. It mentions the need for an 'exact name', which adds some behavioral context, but fails to disclose critical traits such as authentication requirements, potential rate limits, error handling, or what happens if the chat doesn't exist. This leaves significant gaps for a mutation tool.

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 a single, efficient sentence that directly states the tool's action and key requirement ('exact name'). It is front-loaded with no wasted words, making it highly concise and well-structured.

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 complexity as a mutation operation with no annotations and no output schema, the description is incomplete. It lacks information on behavioral aspects like permissions, side effects, or response format, which are crucial for effective use by an AI agent.

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 100%, so the schema already documents both parameters ('chatName' and 'message') with clear descriptions. The description adds minimal value by reinforcing the 'exact name' requirement, but doesn't provide additional syntax or format details beyond what the schema provides.

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 ('send') and resource ('message'), and identifies the target ('chat by its exact name'). It doesn't explicitly differentiate from siblings like 'connect_whatsapp' or 'list_chats', but the action is distinct enough to imply 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 implies usage by specifying 'Select a chat by its exact name', suggesting it's for sending messages to known chats. However, it doesn't provide explicit guidance on when to use this tool versus alternatives like 'list_chats' for finding chats or 'connect_whatsapp' for setup, leaving some ambiguity.

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