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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The description adds only the mild implication that results are Meta-provided, unclaimed candidates; it says nothing about how many suggestions come back, whether they expire, or whether re-calling yields the same set.

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?

A single front-loaded sentence with no filler or redundancy; every word carries information.

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 read tool with a full schema and annotations that cover safety, the description is minimally adequate. It omits the workflow context (what to do with the suggestions) and any hint about the shape of the returned suggestions, which matters slightly since there is no output schema.

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 both parameters are already documented in the schema and the baseline is 3. The phrase 'for a phone number' loosely gestures at phone_number_id but adds no format or sourcing detail beyond what the schema's own descriptions provide.

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 ('Get') and a specific resource ('Meta's available username suggestions') scoped to a phone number, which cleanly separates it from the sibling username_get/set/delete tools. It does not, however, explicitly name those siblings or state how it differs from them beyond the word 'suggestions'.

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 when-to-use guidance at all. The description never says this is the discovery step that precedes whatsapp_username_set, nor does it mention any prerequisite (e.g. that the number must be verified or that profile_id/phone_number_id must come from profiles_placements).

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