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

Goes well beyond the annotations by disclosing the return payload (ranked title/URL/snippet/date, direct answer or knowledge panel, related searches), the billing model ($0.006 USDC per call via x402), and precisely which outcomes are and are not charged (empty results are an error and free; 400/4xx/5xx not settled). That cost/settlement detail is exactly the behavioral context an agent needs before calling a paid 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?

Front-loaded with purpose, then return shape, then sibling routing, then billing — a sensible ordering where each sentence carries information. The three-sentence payment passage is slightly verbose relative to the rest, but it is decision-relevant for a paid call rather than 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?

With no output schema, the description compensates by describing the result structure (title, URL, snippet, date, optional direct answer/knowledge panel, related searches) and the cost/error contract. Nothing an agent needs to select or invoke this correctly is missing.

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 num, query, country, language and time_range are already documented in the schema with defaults, patterns and enums. The description mentions filtering by country, language and recency but adds no syntax or semantics beyond what the schema states, so baseline 3 applies.

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?

Opens with a specific verb+resource ("Answers any question that needs the live web") and immediately scopes the domain with concrete example queries. It also distinguishes itself from the retrieval siblings by naming web_search_read and scrape_markdown, so an agent can tell the three apart without opening schemas.

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?

Explicitly routes the agent: use web_search_read when you also need page contents, or scrape_markdown on an individual result, and notes the country/language/recency filtering available for narrowing. It does not state when *not* to reach for general web search (e.g., preferring sec_full_text_search for filings), so the guidance is strong but not exhaustive.

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