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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety bar is low. The description nonetheless adds real context: the value is read live from the carrier, and it enumerates the non-connected states (waiting, expired, failed) that the annotations cannot convey. It stops short of stating freshness/latency expectations or what triggers a state change.

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, zero filler, with the core action ('Check whether WhatsApp is connected') front-loaded ahead of the state semantics. Every clause carries information the agent needs.

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?

An output schema exists, so return-value structure need not be restated; the description instead supplies the meaning of the returned states and the carrier-read caveat, which is exactly the residual burden for a single-parameter read-only status tool.

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 0% and business_id carries no description, so the schema does nothing here. The description only implicitly scopes the parameter ('a business's KaiCalls number'), which hints that business_id selects the owning business but adds no format, source, or example detail. Baseline 3 given the thin schema.

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 states a specific verb and resource ('Check whether WhatsApp is connected on a business's KaiCalls number') and pins the relationship to WhatsApp verification, so the agent can distinguish it from connect_whatsapp. It does not, however, contrast itself with adjacent status siblings like get_channel_status or get_phone_system_status.

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 rather than stated: the agent can infer this is the read-side counterpart to connect_whatsapp for verifying whether a number is live on WhatsApp. There is no explicit when-to-use, when-not-to-use, or named alternative (e.g., 'check before calling connect_whatsapp').

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