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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=false and destructiveHint=false, so the safety profile is fully covered structurally. The description adds nothing beyond that — not whether unknown IDs error or return empty, nor what fields 'information' comprises.

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. It is appropriately terse, though the brevity reflects under-specification rather than economy of useful detail.

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 two-parameter, read-only lookup with no output schema, the definition is minimally viable. Still, it never says what information is returned or how results differ from the sibling contact/group getters, which is the main ambiguity an agent would face.

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%, with chat_id documented as 'Contact or group ID' and instance_id as 'WhatsApp instance ID'. The description's phrase 'contact or group' merely restates the schema, so the baseline of 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 (get) and resource (information about a contact or group), so the basic operation is unambiguous. However, it does not differentiate from close siblings like whatsapp_get_contacts, whatsapp_get_group_data, or whatsapp_get_contact_avatar, leaving the agent to guess which getter returns what.

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?

No guidance on when to use this versus whatsapp_get_contacts (list) or whatsapp_get_group_data (group details), and no prerequisites or exclusions are given. The agent must infer selection from the name alone.

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