google ads generate keyword historical metrics

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds the meaningful trait 'planless' (a distinct behavioral characteristic not present in annotations) and clarifies it is a read-only operation. It does not contradict annotations and provides some extra context beyond the safety profile, though it omits details like rate limits or error behavior.

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 two sentences and front-loads the purpose. The first sentence is dense but efficient, listing the key outputs. It avoids fluff, though the output enumeration could be considered somewhat detailed; still, it is appropriately sized for a complex tool and does not repeat schema content.

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?

Given the tool's complexity (12 parameters, output schema present), the description gives a solid high-level overview. It does not mention alternatives or special flags like includeMonthlySearchVolumes for trimming responses, but those are covered in the schema. The description is sufficient for an agent to understand the tool's purpose and basic behavior without missing critical information.

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 100%, so the schema fully documents all 12 parameters. The description does not add any parameter-specific guidance beyond what is in the schema; it only lists outputs. Per the calibration baseline, a 3 is appropriate since the schema carries the parameter semantics.

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 fetches Keyword Planner search-volume history for supplied keywords, enumerating the exact data returned (average monthly searches, monthly volumes, changes, competition, CPC ranges, etc.). It also labels itself as a 'read-only planless RPC,' which distinguishes it from the forecast and ideas siblings without naming them explicitly.

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 implies usage through the word 'historical' and the contrast with forecast/ideas siblings, but it does not explicitly state when to use this tool versus alternatives such as google_ads_generate_keyword_forecast_metrics. There are no explicit exclusions or conditions. The purpose is clear enough that an agent can infer, but the guidance is not spelled out.

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