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

Annotations already cover the safety profile (read-only, open-world, idempotent, non-destructive), so the description only needs to add context. It does: it discloses that results span every ending and are returned with a defensibility state (sellable, restricted, not ours to sell, taken, not checked), which tells the agent to expect heterogeneous, partly negative results rather than a plain list of available names.

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?

Three short sentences: purpose, result shape, and input constraint. The critical usage rule is front-loaded alongside the purpose, and no sentence is redundant with the schema or annotations.

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?

With a rich annotation set and an output schema, the description only needs to orient the agent, and it does so — purpose, input constraint, and result taxonomy are all present. Minor gaps remain (no note on result volume or how the open-world lookup behaves), but nothing required for a correct first call 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% for the single parameter, so baseline would be 3. The description goes beyond the schema by constraining the input type — a concept, not a domain — which prevents a common misuse that the schema's example ("calm inbox") only hints at.

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 and resource — find domain names for an idea — and clarifies the return shape (candidate names across every ending with a status label). It implicitly separates itself from domain-checking siblings like audit_domain or check_live by insisting on a concept rather than a domain, but it never names suggest_names or scan_namespace, which are the closest-looking alternatives.

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?

"Pass the concept, not a domain" is an explicit, actionable usage constraint that steers the agent away from the domain-oriented siblings. It gives clear context for when this tool applies, though it doesn't explicitly enumerate when to prefer suggest_names or scan_namespace instead.

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