wa_send_message

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

Annotations already declare readOnlyHint=false, destructiveHint=false, and openWorldHint=false. The description adds a critical runtime dependency not captured by annotations or schema: the Firefox Bridge, WhatsApp Web, and the bridge extension must be active. It does not explain delivery semantics or failure behavior, but the prerequisite is a meaningful behavioral disclosure.

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 two concise sentences: the first front-loads the action, and the second supplies the necessary prerequisite. There is no redundant or wasted 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?

For a simple two-parameter send tool with full schema coverage and safety-relevant annotations, the description covers the purpose and the key environmental requirement. It could say more about expected output or failure modes, but no output schema exists and the tool is low-complexity.

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 is 100%, and the schema already documents both parameters, including that 'chat' is a substring match and 'message' is the text to send. The description adds no further parameter semantics beyond what the schema provides, so the baseline of 3 is appropriate.

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: 'Send a WhatsApp message via Firefox Bridge.' This clearly distinguishes it from sibling tools like wa_list_chats and wa_read_messages, which list and read rather than send.

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 a clear operational prerequisite: Firefox must be running with WhatsApp Web open and the bridge extension active. It does not explicitly name when-not to use it or point to alternatives, but the context is sufficient for this simple tool.

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