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

Annotations declare readOnlyHint=false and destructiveHint=false, but the description goes further by explicitly flagging it as a write operation, explaining the confirm=false preview behavior, and warning about participant notification irreversibility and potential ToS-based account restrictions. This adds substantial value beyond the annotations and does not contradict them.

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 three sentences, front-loaded with the core action and immediate warning. Every sentence conveys critical information—what it does, the irreversible notification, the confirm flag workflow, and the prerequisite/safety warnings. No 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?

Given the tool's complexity (write operation with confirmation), the description covers prerequisites (resolve numbers), the confirm workflow, irreversibility, and ToS warnings. The output schema is present, so return details aren't needed in the description. An agent has everything needed to invoke correctly and safely.

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 schema already documents all parameters. The description adds contextual meaning by explaining the confirm parameter's role in the preview vs. creation flow and by referencing E164/JID formats for participants, which the schema also mentions. Slight overlap but the description reinforces and clarifies the workflow, so a 4 is warranted.

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+resource (creates a WhatsApp group), names the key parameters, and clearly differentiates from siblings like whatsapp_send_message by focusing on group creation. The purpose is unmistakable.

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?

Explicitly instructs when to use this tool: resolve numbers first with whatsapp_search_contacts, and explains the confirm workflow (preview vs. actual creation). It also warns about the irreversible nature of notifying participants, giving clear usage context.

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