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

Annotations already declare the operation is non-read-only and non-idempotent; the description adds useful behavioral detail by stating it 'Reports who was unblocked' with number, name, and country. It does not mention error paths or reversal via re-blocking, but it does not contradict the 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?

Two focused sentences with no filler; the action is front-loaded and the return-behavior sentence is the only extra 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 tool with annotations and an output schema, the description supplies the core semantics, account scope, and report behavior. It could add explicit error or repeated-call handling, but nothing essential for invoking the tool correctly is missing.

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 coverage is 100%, so the baseline is 3; the description does not add parameter-level detail. One caveat: the schema's jid property says 'the contact to block' instead of 'unblock', a typo the description should have corrected, and this prevents a higher score.

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 opens with a specific verb and resource: 'Unblock a previously blocked contact on one of your WhatsApp accounts.' It clearly distinguishes itself from siblings like wa_block_contact by stating it reverses a prior block, and it promises a concrete report of the unblocked contact.

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?

The phrase 'previously blocked contact' gives a clear precondition: use this only when unblocking an existing blocked contact, not for creating blocks. It does not explicitly name alternatives such as wa_block_contact or wa_list_blocked, so it stops short of full when/when-not guidance.

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