Preview Pending Keyword Activation

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

The description states 'without changing anything,' which matches the readOnlyHint annotation, and it explains the meaning of specific output values (e.g., immediateCharge 0 with isUpgrade false means free). This goes slightly beyond the annotation by providing interpretive context, though it does not mention potential side effects or error conditions beyond the read-only guarantee.

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 slightly longer than necessary but every sentence adds value: it states the purpose, the lack of inputs, the computation logic, the output fields, and usage distinctions. It is front-loaded with the most critical information and does not contain redundant fluff.

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 description fully covers the tool's context: when to use it, what it computes, what the output fields mean, and how it differs from the sibling preview_keyword_billing. Since an output schema exists, the description need not enumerate all return fields, but it still provides valuable interpretation of key output semantics.

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?

The tool takes no parameters (schema coverage 100%), so there is nothing to explain. Per the rubric, 0 parameters receives a baseline score of 4. The description correctly omits any parameter details, and no additional clarification is needed.

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 clearly states the tool's purpose: previewing the billing impact of activating pending keywords. It uses a specific verb ('preview') and resource ('billing impact of activate_pending_keywords'), and explicitly contrasts it with the sibling tool preview_keyword_billing, making the distinction unambiguous.

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 gives explicit usage guidance: 'Use this right before activate_pending_keywords' and 'Use preview_keyword_billing instead to price an arbitrary keyword count, for example before add_keywords or enable_keyword.' This clearly tells the agent when to use this tool versus the alternative, leaving no ambiguity.

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