update_bid

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

Annotations already indicate mutation (destructiveHint=true) and idempotency (idempotentHint=true). The description adds context about echoing old and new values, overwriting the prior bid, and immediate application, which clarifies behavior beyond 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 three sentences, each adding unique value: action+echo, overwrite+immediacy, and differentiation. No redundant or extraneous information.

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 simple 2-parameter mutation tool with full schema coverage and clear annotations, the description covers core behavior and provides an alternative. It lacks error conditions or permission requirements, but these are not critical for the tool's simplicity.

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% with clear descriptions for both parameters (bid_usd and ad_group_id). The description does not add new parameter details beyond what the schema provides, so baseline score of 3 is appropriate.

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 action 'Set an ad group's bid in USD', specifying the verb (set) and resource (bid on ad group). It distinguishes from sibling tool 'update_budget' by explicitly noting its purpose.

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 provides explicit guidance to use 'update_budget' for capping daily spend, helping differentiate from a key alternative. It also implies the tool is for immediate, one-off bid adjustments, though it doesn't list prerequisites or typical use cases.

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