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

Annotations already indicate destructiveHint=true and idempotentHint=true. The description adds valuable behavioral context by explaining the consequences for the blocked contact (cannot message or see profile), which goes beyond 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?

Only two sentences, front-loaded with the core action, and every word serves a purpose. No redundancy or fluff.

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 straightforward block operation, the description covers the effect on the contact and implies it is permanent (unless undone via unblock). No output schema exists, but the consequences are sufficiently explained.

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% and both parameters ('jid' and 'channelId') are well described in the schema. The description does not add additional parameter-level details, so a baseline of 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 uses a specific verb ('Block') and resource ('WhatsApp contact'), and clearly states the consequences (cannot message the bot or see its profile), easily distinguishing it from siblings like 'unblock_contact' or 'delete_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 description provides clear context on what blocking does but does not explicitly guide when to use it versus alternatives (e.g., 'unblock_contact', 'mute', or 'delete_contact'). No when-not-to-use or alternative references are included.

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