List WhatsApp instances

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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so safety is covered; the description reinforces it with 'Read-only' and adds the prerequisite role in the tool graph. It stops short of mentioning pagination or ordering behavior for large accounts, which is the only remaining behavioral gap.

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?

Three short sentences, front-loaded with what it is, then the ordering constraint, then the safety note. No repetition of schema or annotation content beyond a one-word reinforcement.

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?

With no parameters and no output schema, the description carries the load well by enumerating returned fields and stating the call-ordering requirement. Only pagination/volume behavior for accounts with many instances is unaddressed.

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?

Zero parameters, so the baseline is 4. The description usefully documents what the result rows contain (id, name, phone, status), which matters since no output schema exists.

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?

States a specific verb+resource (lists WhatsApp instances) plus the scope (all instances in the account) and the fields returned (id, name, phone, status). It is immediately distinguishable from siblings like get_instance_status, which targets one instance.

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?

Explicitly instructs 'Call this first to discover the instance_id that every other tool needs', which is a concrete ordering rule rather than vague advice. An agent knows both when to call it and why, relative to the many instance-scoped siblings.

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