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

Annotations provide readOnlyHint=false, idempotentHint=true, and destructiveHint=false. Description adds critical behavioral context: token validation, success sending broadcasts, failure with VALIDATION_ERROR, and the limitation that delivery/read stats won't update (due to webhook wiring). This goes beyond annotations, explaining side effects and constraints.

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?

Description is a single paragraph but front-loaded with the core action and alternative context. Each sentence adds value: the flow, validation, return, failure mode, and caveat. Slightly verbose but justified given the complexity of the tool.

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?

All necessary information for an agent to call correctly is present: required parameters, how to gather them, expected return shape, error behavior, and a key limitation (stats won't update). No output schema but description clearly states the return values. Comprehensive for a connection tool with 3 params.

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 covers 100% of parameters with descriptions, so baseline is 3. Description adds practical guidance on what each parameter is (e.g., 'permanent access_token', 'phone_number_id', 'waba_id') and how the user should obtain them from Meta app setup. This enriches schema descriptions by connecting them to the usage flow.

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?

Clearly states it connects a workspace's WhatsApp by using user-provided credentials, explicitly framing it as the 'bring your own credentials' alternative to the browser signup popup. Distinguishes from sibling tools like whatsapp_connect_link and disconnect_whatsapp.

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: 'Use this to connect a workspace's WhatsApp number entirely in chat' and describes the exact workflow of asking the user for three values. Mentions alternative (browser signup popup) and differentiates from disconnect_whatsapp implicitly.

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