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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world, so the safety profile is covered. The description adds the useful behavioral fact that it relies on the customer's own data and needs no Keyword Planner approval, but says nothing about how the three categories are surfaced or any limits/thresholds applied internally. Adds some value but not rich behavioral context.

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?

Front-loaded with the core purpose and then the three ordered categories, with the one parameter note last. Dense but every sentence earns its place; the parenthetical about Keyword Planner approval is justified because it changes the routing decision. Slightly list-heavy but efficient.

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?

The tool is fairly rich (output schema exists, so return values need not be re-explained), and the description covers the analytical categories well. The gap is the unexplained 'min_waste' threshold, which governs how the second and third categories are scoped, leaving an agent unable to tune the behavior 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 must carry all parameter meaning. It only explains 'days' ('number of days to look back') and leaves 'min_waste' (default 50) and the required 'customer_id' completely unexplained. Two of three parameters remain opaque, so it does not compensate for the coverage gap.

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 (assessment of keyword/search-term data) and enumerates three concrete output categories: converting search terms not yet added, spend-without-conversion keywords, and low quality-score keywords. It also distinguishes itself from the keyword_planner sibling by noting it works off existing customer data. An agent can tell what it produces without opening the schema.

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 gives clear context for when this is the right call ('does NOT require Keyword Planner approval, works with existing access'), which implicitly routes the agent away from keyword_planner. However, it never addresses overlapping siblings like keyword_quality_report or search_terms_report, whose territory item (3) and item (1) partially cover. Clear context, but no explicit exclusions.

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