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

With no annotations provided, the description fully discloses behavioral traits. It states this is a READ operation ('searching never reserves, registers, or charges anything'), explains the response markers (exact_domain, exact_check_unavailable, no marker), describes the output format and sorting, warns about pricing traps, and instructs how to handle sandbox results. It even specifies when not to take actions like calling the purchase link.

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?

The description is long but highly structured and each sentence serves a purpose. It front-loads the core purpose and usage, then details markers, return format, warnings, and stopping behavior. Although somewhat lengthy, the density of actionable information justifies its size. Minor redundancy could be trimmed, but overall it remains well-organized and readable.

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 tool is complex, and the description covers all aspects: input usage, behavior, output markers, sorting, pricing traps, sandbox caveats, and when to stop. It even provides guidance on related tools and next steps. The output schema exists, but the description adds crucial context about markers and sorting that the schema likely doesn't convey, making the description complete for an agent to use correctly.

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 0% since the description does not directly describe the 'query' parameter. However, the description compensates extensively: it explains exactly what to put in the query (keyword, single full domain, even inside a phrase), how the tool interprets it, and the consequences of multiple domains. This is far more than the bare schema provides, guiding the agent on both valid inputs and expected interpretations.

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 states a specific verb+resource: 'Search real-time domain availability and prices (via Name.com).' It clearly distinguishes from sibling check_domain by explaining the difference: search_domains handles keyword suggestions or one domain for an exact check, while check_domain is used for per-domain checks. The purpose is unambiguous and correctly differentiates from related tools.

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?

The description provides explicit when-to-use guidance: pass a keyword for suggestions, or include one full domain for an exact check. It also gives when-not-to-use instructions: if the user asks about specific domains, use check_domain per domain. Additionally, it explicitly instructs NOT to call get_domain_purchase_link in the same turn and explains why, setting clear boundaries for the agent's behavior.

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