Send a WhatsApp file attachment (PDF, image, document)

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

Beyond the annotations (destructiveHint=true, readOnlyHint=false), the description discloses important side effects: it automatically focuses/opens the WhatsApp Desktop conversation, is gated by an MCP elicitation prompt showing details, has conservative rate limits (5/min, 30/day), and is subject to WhatsApp ToS restrictions. This adds meaningful behavioral context the annotations alone do not convey.

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 compact and front-loaded: core action first, then source of chat_id, then side effects, then limits and policy. Every sentence provides actionable information 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?

Given the presence of an output schema and annotations, the description covers purpose, parameter provenance, side effects, rate limits, and policy cautions. The main gap is the lack of detail on file_path format or file constraints, which would make it fully self-sufficient.

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 must compensate. It clarifies chat_id as an opaque ID from list_chats/search_contacts and notes that caption is optional, but it leaves file_path underspecified regarding format, local vs remote path, or size limits. These additions are useful but do not fully cover all parameter semantics.

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 states a specific verb and resource: sending a file attachment to a resolved chat, and explicitly contrasts with text by mentioning 'optional caption' and file types. It also names the chat_id source (list_chats / search_contacts), distinguishing this from sibling send_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 gives clear context: use for file attachments, requires a resolved chat_id from list_chats/search_contacts, and warns about rate limits and WhatsApp ToS. It does not explicitly name an alternative such as send_message for text-only messages, so it stops short of full when-not guidance.

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