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

Annotations already declare readOnlyHint=false, destructiveHint=false, openWorldHint=true, so the safety profile is partly covered. The description adds a genuinely non-obvious behavioral fact — that the call draws down a metered contact allowance — but omits what happens on exhaustion, whether results are cached, and what a lookup actually returns.

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 short sentences, front-loaded with the action and scope, no filler. It is efficient, though the small size reflects thin content rather than disciplined editing.

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?

A four-parameter, all-required, credit-consuming tool with no output schema and 0% parameter coverage needs the description to carry more than it does. Nothing explains the identifier parameters, the idempotency requirement, or the shape of the result.

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 0% across four required parameters, and the description documents none of them. It only vaguely implies site/prospect scoping, and says nothing about idempotencyKey, which is the parameter most in need of explanation given the metered, retryable nature of the call.

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: look up a contact / who to email at a prospect's site. An agent can distinguish this from siblings like select_prospect_contact or verify_contact, though those distinctions are only implied, not stated.

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 says it consumes the plan's contact allowance, which hints at cost but gives no explicit when-to-use, when-not-to-use, or alternative (e.g. select_prospect_contact vs a fresh lookup). No prerequisites or sequencing guidance.

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