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

Annotations already declare readOnly, idempotent, openWorld, and non-destructive, so the safety profile is covered. The description adds a genuinely decision-relevant behavior that structured fields do not carry: the $0.10 USDC cost per call. It stops short of describing the masked-vs-unmasked result behavior (only implied via the schema's x_api_key/payment_signature descriptions), but the pricing disclosure is real added value.

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, value proposition front-loaded with price, components enumerated second. Nothing is wasted and the ordering is sensible for quick scanning. Marketing phrasing ('Complete 4-in-1') is mild and does not obscure the content.

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 schema fully documents parameters and annotations cover safety, so the basics are present. But for a composite, payment-gated tool with 5 params and no output schema, the description omits the key operational nuance an agent needs: that results are masked unless a prepaid pass or x402 payment is supplied, and how this overlaps the individual sibling tools. Adequate but with clear gaps.

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 the schema already documents all five parameters (domain, company, location, x_api_key, payment_signature). The description adds no parameter-level meaning beyond that; at best 'local business contact/phone leads' loosely hints at the location parameter. Baseline 3 is appropriate when the schema does the heavy lifting.

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 names a concrete deliverable (B2B sales/competitive intelligence dossier) and enumerates the four data domains it aggregates: DNS/MX/SaaS tech stack, website extraction, local contact/phone leads, and social mentions. An agent can form a clear picture of the output. However, it never distinguishes itself from the sibling tools that perform these same tasks individually (domain_intel, web_extract, maps_leads, social_search), so differentiation is missing.

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?

There is no guidance on when to pick this bundled dossier versus calling the individual sibling tools (domain_intel, maps_leads, web_extract, social_search) that cover the same ground. No prerequisites, no exclusions, no alternative routing. The agent is left to infer usage entirely.

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