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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds valuable behavioral context beyond annotations: it reveals that the response includes a 'next_step' that should be repeated to the user, and it describes the contents of the state. No contradiction with annotations.

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?

The description is two sentences with zero wasted words. The key functional information is front-loaded, and the usage guidance is concise and actionable. Every sentence serves a purpose.

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 read-only tool with full schema coverage and safety annotations, the description is quite complete. It explains what state is read, when to call it, and hints at a 'next_step' in the response. It does not fully detail the response structure, but this is a minor gap given the tool's simplicity and the mention of next_step.

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?

The input schema fully documents the only parameter, agent_id, with a clear description ('Optional: report only this agent's WhatsApp state.'). The tool description does not add any additional meaning about this parameter, so it relies entirely on the schema's coverage, which is already complete. Baseline 3 is appropriate.

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 clearly states the tool's purpose: reading the WhatsApp state of the connected account, listing specific aspects (owner's phone verification, platform numbers, conversation-agent routing). It uses a specific verb ('Read') and resource, and is easily distinguished from sibling tools like attach_agent_whatsapp and detach_agent_whatsapp because it is explicitly read-only.

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?

Provides explicit guidance: 'Call this first whenever the user asks to talk to an agent on WhatsApp' and instructs to repeat its 'next_step'. This gives clear when-to-use context, but it does not explicitly mention when not to use it or name alternative tools, so it falls just short of a 5.

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