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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), and the description adds non-obvious operational facts: statelessness, a 32 KB payload cap, 60 RPM throttling, demo mode or L402 payment at 10 sats, and HTTP 400 on invalid input. These are runtime constraints an agent could not infer from the schema or annotations, which is exactly what this dimension rewards.

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?

Purpose is front-loaded in the first sentence, followed by usage then runtime constraints, with no filler. The final sentence packs size, rate, auth, default, and error details into one dense parenthetical, which is efficient but slightly hard to parse in a single read.

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?

An output schema exists, so return values need no explanation, and the description covers the remaining gaps an agent needs: statelessness, input size, throughput, payment/auth path, and failure code. Nothing material for a correct invocation 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 coverage is 100%, so the baseline is 3, but the description adds the non-defaulted value that extraction_focus defaults to 'all_contacts' – information the schema itself does not state. country_hint is left entirely to the schema, keeping it below a 5.

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 concrete verb plus four specific resource types (emails, phones, physical addresses, social handles) and the source scope (web text and DOM footers). It explicitly contrasts with parse_html_tables, so the agent can separate it from the closest sibling without reading either 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?

Gives three positive use cases (sales lead research, business contact directories, customer service info) and an explicit exclusion routing structured tabular input to parse_html_tables. The when/when-not pair is fully resolved.

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