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

Annotations already declare readOnlyHint=false, destructiveHint=true, openWorldHint=true and idempotentHint=false. The description adds real behavioral context beyond those flags: the change is asynchronous, the existing name remains in force until Meta approves, and the result is delivered via the placement.name_status_updated webhook rather than the call response. It stops short of covering rate limits or what happens on duplicate pending requests.

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?

Two tight sentences with no filler. The action is front-loaded in the first sentence and the asynchronous outcome mechanism follows immediately as supporting context.

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 output schema, the description correctly explains that the outcome does not come back from the call but arrives on a webhook, which is the key completeness gap for this tool. Missing only secondary details such as permission requirements or whether review can be re-requested while pending.

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 all three parameters (profile_id, phone_number_id, display_name) are already documented in the schema, including the pointer to profiles_placements for phone_number_id. The description adds no further parameter detail, which is the expected baseline when the schema does the heavy lifting.

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 gives a specific verb ('Submit') and resource ('a new display name') and frames the operation as an asynchronous Meta review request, which clearly separates it from whatsapp_display_name_get (read) and whatsapp_username_set (a different identifier). An agent can identify the action without opening the schema.

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?

Usage is implied by the verb and by the note that the current name stays until approval, so an agent infers this is a request-to-change rather than a check. However, there is no explicit when-to-use guidance, no mention of checking current state first (e.g., whatsapp_display_name_get), and no stated prerequisites such as whether a request can be pending concurrently.

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