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

Annotations only cover the safety profile (readOnly, openWorld, non-idempotent, non-destructive); the description adds the economically important behavior an agent cannot get elsewhere — pay-per-profile in stablecoins, no charge on a miss, and the deliverability criterion ('not a catch-all domain') plus a returned status and quality score. This also explains the non-idempotent hint: repeat calls cost money.

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 dense sentences with the capability front-loaded and pricing/edge-case handling in the tail; nearly every clause carries new information. Slightly packed in the second sentence, but there is no filler or marketing padding.

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?

There is no output schema, so the description takes on the burden of describing the return payload, and it does so field-by-field while also covering the billing edge case (no verified email = no charge). For a single-parameter, paid, one-shot lookup, nothing an agent needs to invoke it correctly is missing.

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% and the single 'url' parameter is fully documented there (https only, no query string, maxLength 2048). The description only restates 'one LinkedIn profile URL ... one profile per call', adding no format or syntax detail beyond the schema, so the baseline of 3 applies.

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+resource ('send one LinkedIn profile URL and get the public profile ... plus the work email') and enumerates exactly which fields come back (headline, about, location, positions, education, skills). The differentiator against the sibling 'linkedin' tool — the verified, deliverability-checked email — is stated up front, so an agent can pick between them without opening a 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?

Usage is implied rather than routed: the description establishes that this is the tool for profile + work email and constrains it to one profile per call, but never names the obvious alternative ('linkedin' for profile data without email) or states when not to use this paid endpoint. The billing note ('a profile with no verified email is not charged') is useful context but not a selection rule.

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