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

Annotations only declare readOnlyHint/openWorldHint, yet the description adds substantial behavior: a quote-then-pay flow, x402 payment on Base, exact quoted amount, rows without data never charged, a $1 cap, quote expiry of 15 minutes, and 3 free scans per IP per day. That is exactly the extra context annotations cannot carry.

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?

Dense but front-loaded: purpose first, then Step 1, Step 2, then caps/expiry. Nearly every clause carries operational information, though the pricing and rate-limit details could be tightened slightly.

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?

For a two-phase paid tool with an output schema already defined, the description covers everything an agent needs to invoke it correctly: which mode to send, what payment follows, cost ceilings, expiry, and free-scan limits. Nothing material 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 67%, and the description compensates by explaining the role of each parameter in the sequence: {tool, domains} for the free step, {quote_id} alone for payment, plus the 50-domain cap (33 for company-profile). Domain formatting is left to the schema, so it is not a full 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 and resource ('Bulk company lookup: run one tool ... on many domains with one payment') and names the five underlying lookup types, which cleanly distinguishes it from the single-domain siblings such as detect_website_tech_stack and get_company_open_jobs.

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?

It clearly frames when this tool applies (many domains, one payment, one underlying tool) and spells out the two-step call sequence. It stops short of explicitly naming the single-domain siblings as alternatives, so the routing is implied rather than stated.

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