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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds genuine value beyond that by disclosing the credit cost and the output shape (Markdown with named sections), but it says nothing about rate limits, pagination semantics, or what happens when Google is unavailable with the default engine.

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?

Two short sentences with zero waste: the action first, then the return shape and cost. Nothing is buried and nothing is redundant.

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 16-parameter tool with no output schema, the description adequately covers what is returned (named result sections, Markdown) and the base cost, while the rich schema covers parameter behavior. The main residual gap is that engine fallback behavior and multi-credit combinations are left entirely to the schema rather than being framed at the definition level.

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 94%, so the schema already documents nearly every parameter, including the engine list and cost implications of num/include_answer/include_content. The description only restates baseline cost ('1 credit'), which the schema partially duplicates for the paid options; baseline 3 is correct when the schema does the heavy lifting.

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 ('Search Google') and enumerates exactly what comes back (organic results, answer box, knowledge graph, People-also-ask, related searches) as Markdown. That makes it distinguishable from news/images/scholar/videos siblings, though it never names those siblings 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?

No statement about when to choose this over the 18 sibling tools (news, images, scholar, maps, answer, research) and no prerequisites or exclusions. The only guidance-adjacent content is a cost note ('1 credit'), which informs budget but not tool selection.

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