Post to a group/chat (requires confirm)

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

Annotations only declare write/open-world/non-destructive; the description adds the crucial behavior that calls are preview-only by default and that confirmation is a two-step human-approval gate. It also discloses dual-provider routing, which the annotations do not.

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 tight sentences with no filler; the preview/confirm safety gate is front-loaded and the provider routing is stated compactly. Every clause carries information.

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 6-parameter write tool with no output schema and no parameter descriptions, the description covers the safety gate, the return-shape caveat (preview), and routing. Remaining gaps are chatId formatting and attachment field dependencies, which an agent may need before calling.

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 0%, so the description must carry the load. It explains confirm and the green/cloud provider enum meaningfully, and gestures at fileUrl via 'image/file URL', but chatId format (phone vs group id) and the fileName/fileUrl relationship are never clarified.

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 and resource (send a message to a group/chat) and disambiguates the two delivery paths: Green API for groups/chats versus WhatsApp Cloud API for individuals. An agent can distinguish it from draft_post and schedule_post without opening any 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 an explicit conditional flow: without confirm:true it only previews, and confirm:true should only be set after the user explicitly approves the exact text and destination. It does not, however, say when to choose this over draft_post or schedule_post, which are the nearest siblings.

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