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

Annotations already declare idempotent=true and destructive=false, so the safety profile is partly covered; the description adds the non-obvious side effect that an in-progress pairing is cancelled, plus that no re-pairing is needed. It does not mention expected downtime, impact on queued/in-flight messages, or how to confirm the restart succeeded.

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?

Three short sentences, front-loaded with purpose followed by triggers then the exclusion. No filler, no restatement of the title.

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 zero-parameter, non-destructive, idempotent action with no output schema, the description covers purpose, triggers, and the main hazard. It stops short of telling the agent what to do afterwards, e.g. verifying recovery via get_session_status, which would make it fully self-sufficient.

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?

Zero parameters, so there is nothing for the description to disambiguate; baseline 4 applies. The description correctly implies a no-argument, single-target operation.

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 (reconnects) and resource (WhatsApp session) plus the key scope constraint: no new QR code or re-pairing. That constraint alone separates it from get_pairing_qr and unlink_whatsapp without opening either 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?

Gives three concrete trigger conditions (session stuck, messages not sending, stale connection state) and an explicit exclusion with the reason (do not use during pairing, it cancels the pairing in progress). Both when-to-use and when-not-to-use are covered.

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