subdomain_timeline

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so the safety profile is fully covered. The description adds interpretive framing about what bursts mean, but says nothing about downstream behavior (resolution, whether empty months appear, data sources). Modest added value against rich annotations.

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 short sentences, front-loaded with what the tool returns. The second sentence is interpretive rather than structural but still earns its place as usage framing. No filler.

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-shape explanation is not required, and annotations carry the safety profile. However the underexplained 'months' parameter and the lack of any differentiation from the overlapping sibling tools leave an agent with real gaps when choosing between them.

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?

At 67% schema description coverage, the description is expected to compensate for gaps. The 'months' parameter has no schema description and the description never mentions it; response_format is likewise untouched. Only 'domain' is well documented, and that comes from the schema itself, not the description.

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 resource and scope: 'New hostnames per month and the product-like names that first appeared each month.' An agent can tell it produces a time-bucketed subdomain inventory. It does not differentiate itself from siblings like new_subdomains or hostname_history, so it stops short of a 5.

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?

'Bursts often line up with launches, rebrands or new regions' implies the tool is for detecting launch/rebrand activity, which is useful context. But there is no explicit when-to-use statement, no prerequisites, and no routing to the sibling tools that overlap in this space.

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