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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds meaningful behavioral context: parameters are passed through unchanged, and the schema's parameter descriptions add details like 'has_more' and 'next_start_row' for pagination. The description itself is brief but the combination with schema descriptions gives good transparency.

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?

A single sentence that front-loads the core purpose and the key pass-through behavior. No wasted words; every part 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?

For a read-only pass-through tool with 100% schema coverage and no output schema, the description plus schema covers the essentials. The only minor gap is that the description doesn't explain what the response looks like beyond the schema's hints about has_more and next_start_row, but for a pass-through tool that's acceptable.

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 already documents all 8 parameters thoroughly. The description adds the key semantic that all parameters are passed through unchanged to Google's API, which helps an agent understand that the schema descriptions mirror Google's own semantics. This is useful but not extensive beyond the schema.

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 states a specific verb ('Direct query') and resource ('Google's Search Analytics API'), and clarifies that parameters are passed through unchanged. It distinguishes itself from higher-level analytics tools by emphasizing the raw, pass-through nature, though it doesn't explicitly name a sibling alternative.

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 this is the low-level tool to use when you want the raw API behavior without abstraction, and the sibling list (top, page_queries, site_overview) suggests the alternatives. It doesn't explicitly state when not to use it, but the 'passed through unchanged' phrasing gives clear context for selecting it over the more processed sibling tools.

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