Estimate backlinks cost

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

Annotations cover the safety profile (readOnlyHint, destructiveHint=false, openWorldHint=false), and the description adds genuinely useful behavioral facts: it is free and does not call a provider, so no budget is consumed. It does not detail the shape of the eligibility result, but the added cost-safety context is valuable.

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 clauses with the key fact ('Free') front-loaded and the sibling routing at the end. Every word earns its place with 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?

For a cost-estimation tool with no output schema and fully documented parameters, the description covers purpose, cost behavior, and the follow-up paid operation. It could state what the eligibility result contains, but nothing essential for correct invocation 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%, so all seven parameters (mode, target, project_id, result_limit, target_scope, max_cost_cents, include_subdomains) are fully documented in the schema. The description adds no parameter-level meaning beyond that, so the baseline 3 applies.

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 (returns/estimates) and resource (cost and eligibility of a backlinks analysis) and explicitly contrasts itself with the paid sibling 'analyze_backlinks'. An agent can tell this is the free pre-flight costing tool without opening the 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?

It names the alternative 'analyze_backlinks' as the paid operation, implying the workflow of estimating here before spending. It is clear context, but there is no explicit when-not-to-use or a statement that this is a required prerequisite, so it falls short of a 5.

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