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

Annotations already declare readOnly/openWorld/non-destructive, so the safety profile is covered. The description adds two genuinely non-structured facts: a cost of 5 prepaid credits per successful call (implying failed calls are free) and that the MCP response is a 'compact view' of the full SERP, warning the agent that results may be trimmed. It does not mention rate limits or result-count ceilings, but the pricing and truncation notes are real added value.

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 resource and output shape, then use cases, then cost – a sensible priority order with no filler. The closing sentence about the 'compact view' is slightly awkwardly placed and would read better folded into the output description, but nothing is wasted.

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?

With no output schema, the description usefully names the returned fields (titles, URLs, snippets, positions) and flags that the MCP view is compact, so an agent knows what to expect back. Pricing is disclosed, which matters for a metered tool. Pagination and the 20-result cap are only in the schema, a minor gap for a five-parameter read tool.

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 every parameter (query, page, results, country, language) is already documented with types, bounds and enums. The description only restates country/language targeting at a high level and adds no syntax, defaults or interaction rules beyond the schema. Baseline 3 applies 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 ('Google Search results (SERP) for a query') and enumerates the returned fields, which is more precise than the bare title. It distinguishes itself implicitly from vertical siblings like search_news or search_scholar by framing itself as the general organic web search, but never names those alternatives.

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?

Offers use-case framing ('source discovery, fact-finding and research') and mentions country/language targeting for localized sources, which implies when to reach for it. There is no explicit when-not guidance and no pointer to sibling tools such as search_news when the intent is news-specific, so the routing decision is left to inference.

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