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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered. The description adds genuine value beyond them: the read is 'live' from Meta (not cached) and it carries a side effect, 'refreshes the placement's stored metadata,' plus the platform_type CLOUD_API-vs-coexistence distinction. No auth or rate-limit detail, hence not a 5.

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 sentences, front-loaded with the core action. The long field enumeration is dense but earns its place given there is no output schema. Minor bloat from the parenthetical explanation, but no filler sentences.

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 field list effectively serves as a return-value spec, and the metadata-refresh side effect is disclosed. Complete enough to call correctly; the only gap is the absence of any routing guidance relative to sibling reads.

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 both parameters (profile_id, phone_number_id) are already documented in the schema. The description adds no syntax, format, or resolution guidance beyond what the schema provides, so baseline 3 applies.

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 ("Read the live state") and resource (a WhatsApp phone number) and enumerates the exact fields returned, which cleanly separates it from siblings like whatsapp_number_register/verify (mutations) and whatsapp_display_name_get (a narrower read). An agent can identify the tool 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 only implied: 'read the live state' suggests use for inspecting a number's current status. There is no explicit when-to-use/when-not or named alternative (e.g., why not whatsapp_display_name_get or whatsapp_business_profile_get for subsets). Adequate but leaves selection to inference.

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