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

No annotations are provided, so the description carries the full burden of behavioral disclosure, and it discloses nothing: no side effects, no authentication requirements, no indication of what happens if quoted_message_id is omitted, and no return behavior.

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 very short, but this reflects under-specification rather than economical writing. As a single fragment it is front-loaded by default but earns nothing for the agent.

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 three-parameter messaging tool with no annotations, no output schema, and no schema descriptions, the definition is wholly inadequate. An agent has no basis for choosing it over send_text or for constructing a correct reply call.

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 0% across all three parameters, and the description adds no parameter meaning at all. In particular, the role of quoted_message_id (optional reply target) versus phone_number is left completely unexplained.

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 is essentially a restatement of the tool name ('reply message') prefixed with a platform label ('WhatsApp Web'). It does not explain what replying entails versus sending a new message, nor does it distinguish this tool from the obvious siblings send_text and converse.

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?

There is no guidance on when to use reply_message instead of send_text, send_media, or converse, and no mention of prerequisites such as needing an existing message or an active chat session. The agent must infer entirely from the tool name.

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