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

Without annotations, the description carries the full burden. It discloses meaningful behavioral traits: searches a verified index rather than arbitrary web content, returns structured cited results, and mentions cost ('a fraction of a cent against the API key's free/credit balance'). It does not mention rate limits or explicit read-only semantics, but the search action clearly implies no mutation.

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?

The description is compact at three sentences, front-loads the primary purpose and output, adds a relevant cost note, and closes with usage guidance. Every sentence adds distinct value with no redundancy or filler.

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 description is reasonably complete for a search tool with no output schema: it lists the returned fields, explains the verified-index scope, and provides cost awareness. It does not cover failure modes or authorization requirements, but for a read-only search operation these are not critical gaps and the essential calling context is present.

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 baseline is 3. The description does not add parameter-specific semantics beyond what the schema already provides; the 'query' guidance and max_results behavior are already fully documented in the input schema. No additional insight is given about parameter formats or edge cases.

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 opens with a specific verb ('Search'), names the exact resource ('Groundlink's verified index (Wikipedia + DuckDuckGo)'), and enumerates the returned fields ('title, url, snippet, source'). This unambiguously explains what the tool does and what output it produces, easily distinguishing it from any guessing or other knowledge retrieval behavior.

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 explicit when-to-use guidance: 'Prefer this over guessing when a factual claim needs verification or a source.' It also implicitly states when not to use it (do not guess) and is the only tool of its kind, so no alternative routing is needed. This is direct and actionable.

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