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

Annotations already declare read-only, idempotent, closed-world behavior, yet the description adds real value: full-month inclusion for any touched month, privacy-threshold suppression, and an auth/plan requirement. It stops short of disclosing pagination or result-size behavior for a 9-parameter listing tool.

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?

Four short sentences, front-loaded with what the tool returns, then scope, caveat, and prerequisites. No filler; 'Preserve privacy thresholds' is slightly telegraphic 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?

An output schema exists, so return values need not be explained, and auth plus aggregation caveats are covered. However, for a 9-param tool with 44% schema coverage, missing guidance on cursor/limit pagination and on choosing accountId vs accountIds vs workspaceId leaves real gaps.

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 only 44% across 9 parameters. The range statement ('Months touched by the range are included in full') usefully explains the days/startDate/endDate interaction, but limit, cursor, groupId, accountId, accountIds and workspaceId get no meaning from the description, and pagination semantics are entirely absent.

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 ('Read stored monthly search keywords for Google Business locations') and clarifies the data is location discovery rather than per-post metrics, which separates it from get_post_performance-style siblings. It does not name the alternative tool directly, so it falls short of a 5.

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 prerequisite context (requires analytics:read and an active paid plan) and implies the domain of use, but never states when to pick this over get_analytics_overview or get_content_insights, nor any when-not condition. Usage is inferable from the purpose line rather than spelled out.

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