send_message

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

Annotations indicate destructiveHint=true. Description adds context about from_id fallback to env var, but does not disclose other behavioral traits like rate limits, error handling, or asynchronous nature.

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?

One concise sentence with essential info (purpose and from_id optionality). No redundant text.

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?

No output schema, but description is sufficient for a simple send action. Does not mention return value or WhatsApp API prerequisites, but given tool's simplicity, completeness is adequate.

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 coverage 67% (2/3 params described). Description adds context for from_id (fallback and discovery method). For wa_id and message, schema already covers format; description does not add beyond schema.

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?

Clearly states 'Envía un mensaje de texto por WhatsApp' (Send a text message via WhatsApp), a specific verb+resource. Distinguishes from siblings like send_attachment, send_template.

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?

No explicit guidance on when to use this tool vs alternatives. Only mentions from_id optionality via env var. Lacks when-not to use or comparison with send_template/send_flow.

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