update_keyword_bid

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

Annotations already indicate this is non-read-only, non-destructive, and idempotent, so the description does not need to restate those facts. The phrase "New max CPC bid" adds some behavioral clarity by showing the update is a direct set operation. It does not disclose additional details such as validation, confirmation behavior, or downstream effects, but it does not contradict the 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?

The description is short, front-loaded with the purpose, and follows with a compact, well-organized argument list. Every line adds value: it defines parameters, clarifies the update target, and provides an example. There is no redundancy or 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 tool with four required parameters and no output schema, the description provides essential call information: the action, the target entity, and all parameter meanings. It does not describe return values or potential errors, but those are not required by the rubric when output schema is absent. Minor gaps remain around validation and side-effect expectations, but the definition is sufficient for an agent to invoke it confidently.

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 0%, so the description carries the full burden of explaining parameters. It provides meaningful definitions for all four parameters, including the relationship of ad_group_id and criterion_id to the keyword, and gives a clear currency example for cpc_bid. This fully compensates for the lack of schema descriptions.

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 action and target: "Update the CPC bid for a keyword." This clearly identifies the tool's resource and verb, and it is distinct from sibling tools such as update_ad_group or update_budget. The resource is unambiguous enough for an agent to select it correctly.

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 intended use is implied by the purpose statement: use this when changing a keyword's max CPC bid. However, there is no explicit guidance about when not to use it or how it compares to related tools like update_ad_group or remove_keyword. The usage context is understandable but not fully articulated.

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