direct_get_keyword_bids

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

Annotations already declare readOnlyHint/idempotentHint/openWorldHint, so safety is covered and 'Read-only' adds nothing new. The description's genuinely additive detail is the one-of-these-ID-filters constraint, which the schema does not encode; it says nothing about pagination behavior or result caps.

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?

Tight, front-loaded sentences with no filler; scope comes first, then mutation and sibling routing. The telegraphic 'Auction data: `direct_get_bids`.' fragment is slightly cryptic but still earns its place.

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?

With an output schema present it need not describe return values, and annotations cover the safety profile. The critical gap it does fill is the required-one-of rule that the schema (0 required params) fails to express; the only shortfall is unaddressed pagination 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?

Schema description coverage is 0%, so the description carries the burden: it names the three ID filter arrays and their exclusivity rule, which is the most important parameter semantic here. It says nothing about limit/offset (500/0 defaults), leaving a fifth of the parameters undocumented in prose.

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 ('Current keyword bids and serving status') plus the exact scoping keys CampaignIds/AdGroupIds/KeywordIds. It explicitly separates itself from the near-name sibling direct_get_bids ('Auction data'), so an agent can pick correctly without opening schemas.

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?

Gives the selection rule ('one required' among the three ID types), routes bid modification to `direct_write` service=bids, and routes auction-price lookups to `direct_get_bids`. Both when-to-use and explicit alternatives are present.

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