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

Annotations only declare readOnlyHint and openWorldHint, so the cost/limit model is genuinely additive: 3 free calls per day shared across all tools, then $0.022 USDC via x402 or card credits, paid in-band via params._meta["x402/payment"]. That is exactly the kind of operational context structured fields do not carry. Minor gaps remain around what happens on failure or which inputs are guaranteed to yield results.

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 no filler, and the deliverable list is well enumerated. The one structural weakness is front-loading the billing quota and payment mechanics ahead of the statement of purpose, which delays the agent's answer to 'what does this do.'

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 prose, and the annotations cover safety. The description covers pricing, bundling, and output readiness. The gap is that both parameters are optional, and the description never says what happens when neither url nor domain is supplied.

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 both url and domain, including that domain is derived from url when omitted. The description adds only a loose mapping of url to contacts/people and domain to profile/tech stack, without new syntax or format detail. Baseline 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?

The description names a specific verb and resource ('Find B2B leads on any company website') and enumerates the concrete deliverables: contact emails, people, company profile, tech stack, and up to 3 email verifications. The phrase 'in one call' implies aggregation vs. the individual sibling tools (company_contacts, company_profile, company_techstack), but it never names them, so the differentiation requires inference.

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 only implied through 'in one call' — the agent can gather this is the bundled alternative to the individual company_* tools. There is no explicit statement of when to prefer this pack over those siblings, nor any prerequisites or exclusions beyond the daily quota.

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