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

Annotations (destructiveHint=true, openWorldHint=true, readOnlyHint=false) already indicate side effects. The description adds real-world impact: 'sends a real message to real people' and 'starts a conversation', emphasizing the need for user confirmation beyond annotation clues.

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?

Three concise sentences: first defines action and target, second explains notifications and account-less usage, third is a critical warning. No wasted words; 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?

The description covers the purpose, real-world consequences, and prerequisites (no account). Although there is no output schema, the description mentions 'starts a conversation' but does not specify return values. For a 7-parameter tool, this is adequate but not exhaustive.

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 description coverage is 100%, so baseline is 3. The description does not add significant meaning beyond the schema's field descriptions (name, email, phone, message, etc.). It does not clarify parameter constraints like 'email or phone required' which is already in the schema.

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's action: 'Send an inquiry on behalf of the user to the advertiser of a listing, a development project, or a real-estate company.' It specifies the verb (send inquiry), resource (advertiser), and context, distinguishing it from sibling tools like reply_to_inquiry or send_whatsapp_verification.

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 explicit context: 'Works without an account' and a strong warning: 'This sends a real message to real people — confirm the details with the user before calling.' It implies when to use (when user wants to contact an advertiser) but does not explicitly exclude alternative tools.

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