mcp-whatsapp

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

Annotations indicate this is a destructive (destructiveHint: true), non-idempotent (idempotentHint: false) write operation (readOnlyHint: false) with open-world data (openWorldHint: true). The description adds valuable context by specifying the media types supported (picture, video, document, raw audio) and the WhatsApp platform, which isn't covered by annotations. No contradiction with annotations exists.

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 front-loads the core purpose without unnecessary words. Every element ('send', 'picture, video, document, or raw audio', 'via WhatsApp') contributes directly to understanding the tool's function.

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 (destructive write operation with 5 parameters) and lack of output schema, the description is minimally adequate. It covers what the tool does but lacks details on return values, error conditions, or side effects (e.g., how failures are handled). Annotations provide safety context, but more behavioral guidance would improve completeness.

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 fully documents all 5 parameters. The description doesn't add any parameter-specific details beyond what's in the schema (e.g., it doesn't explain media format requirements or recipient validation). Baseline score of 3 is appropriate as the schema handles parameter documentation adequately.

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 specific action ('send') and resource types ('picture, video, document, or raw audio') via the WhatsApp platform. It distinguishes itself from siblings like send_message, send_audio_message, send_contact_card, etc., by specifying file/media sending rather than text or other content types.

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 provides no guidance on when to use this tool versus alternatives like send_message for text or send_audio_message for audio recordings. It doesn't mention prerequisites (e.g., media file requirements) or exclusions (e.g., not for sending text-only messages), leaving the agent to infer usage from the name and parameters alone.

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