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

Annotations indicate a write operation (readOnlyHint=false) and possible side effects (openWorldHint=true). Description adds value by explaining the output format (WhatsApp link or email) and the pre-filled message behavior, which annotations don't cover.

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 sentences that are front-loaded with the core purpose, followed by usage specifics. No redundant information; every sentence earns its place.

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 low complexity (2 parameters, simple output), the description covers input sourcing, output format, and the exception case for email. No output schema needed as return values are clearly described.

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%, but description adds practical context: 'message' should be helpful and professional, and 'inquiry_id' comes from 'my_inquiries'. Also explains how 'message' gets pre-filled in the WhatsApp link.

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 clearly states the tool replies to buyer inquiries on listings, using specific verbs and resources. It differentiates from siblings like 'create_lead' or 'my_inquiries' by focusing on composing and returning a pre-filled WhatsApp link or email.

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?

Provides explicit guidance on composing a professional message, sourcing 'inquiry_id' from 'my_inquiries', and handling both WhatsApp and email cases. Lacks explicit when-not-to-use instructions, but context is clear.

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