Estimate domain overview cost

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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds genuinely new behavioral context beyond that: the call is free, does not hit a provider, and returns both cost and eligibility — useful for an agent deciding whether a paid run will succeed.

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?

A single tight sentence with 'Free' front-loaded, followed by what it returns and the paid counterpart. No filler, no redundancy.

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?

No output schema exists, and the description states the return payload (cost and eligibility), which is the key information an agent needs. Combined with 100% schema coverage and read-only annotations, nothing essential is missing for correct invocation.

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% with 8 well-documented parameters (including the enum and the max_cost_cents cache-only note), so the schema carries parameter semantics fully. The description adds no parameter-level detail, making the baseline 3 correct.

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 specific verb and resource (estimate cost/eligibility of a Domain Overview analysis) and immediately scopes it as non-provider-calling. It explicitly names the sibling paid operation analyze_domain_overview, so an agent can distinguish the two without opening either schema.

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 names the paid alternative analyze_domain_overview and frames this tool as the pre-flight check ('Free', 'without calling a provider'), which strongly implies when to use it. It stops short of an explicit directive such as 'call this before analyze_domain_overview' or stating when this check is unnecessary.

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