Monthly search keywords

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

Beyond the readOnlyHint, openWorldHint, and idempotentHint annotations, the description discloses a critical behavioral nuance: insightsValue is a union that can be either an exact value or a threshold for low-volume keywords, and it explicitly warns against summing thresholds as exact counts. It also clarifies that months are calendar months and that the current month's data lags, which is useful for interpreting results.

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 just two sentences. The first establishes the primary purpose, and the second covers the response union and the key caveat about thresholds. Every sentence earns its place, and the most important warning is prominently placed.

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 a union return type and time-sensitive data, the description fully covers the essential aspects: response shape, union semantics, month calendar handling, and the lag. Since the schema already documents all parameters and there is no output schema, this description is complete enough for an agent to invoke the tool and correctly interpret returns.

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?

All five parameters are already thoroughly described in the input schema (100% coverage), including formats, defaults, and the relationship of locationId to list_locations. The description does not add parameter-specific details, such as how startMonth and endMonth interact with the lag, so it remains at the schema-documented baseline of 3.

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 begins with a specific verb and resource: 'Returns the search keywords that surfaced the business on Google, month by month.' This clearly communicates what the tool does and distinguishes it from siblings such as get_daily_metrics or search_chains by emphasizing monthly, keyword-level Google impression data. The title 'Monthly search keywords' reinforces the same.

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 clearly implies when to use this tool—when you need monthly search keyword impressions—and adds practical context by noting that current month data appears with a lag, which helps set expectations. However, it does not explicitly mention alternatives, such as 'use search_chains for chain-level data' or 'use get_daily_metrics for daily trends,' and there are no explicit exclusions.

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