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

Annotations already cover safety (readOnlyHint=true, openWorldHint=true, idempotentHint=false), so the bar is lower. The description goes further with the billing model ($0.003 USDC per call via x402 or prepaid credits), the free-trial status, and the fact that tier and price change when a premium index is connected — material details an agent cannot get from annotations.

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?

Information is front-loaded: sources first, then the tier caveat, then pricing. Dense but each clause carries real content; the pricing sentence is a touch long but it is the differentiating detail.

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?

Covers sources, dedup/ranking behavior, tier volatility, price, and trial status. Since an output schema exists, the listing of return fields is a bonus rather than a necessity, and the only real gap is sibling differentiation.

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 coverage is 100% and both q and limit are fully documented in the schema with bounds and defaults, so the baseline of 3 applies. The description mentions the returned fields but adds nothing about parameter syntax or the 300-character query cap beyond what the schema already states.

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?

Names a specific verb (search) plus the exact source set (Wikipedia, Hacker News, DuckDuckGo instant answers, Stack Overflow) and the result shape (merged, de-duplicated, ranked title/URL/snippet/date). Clear what the tool does, but nothing distinguishes it from the sibling search-open and search-answer tools, which an agent must choose between.

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 explains the tier situation (open-sources now, upgrades to full-web when a premium index is connected) which implies capability boundaries, but it never says when to pick this over search-open or search-answer. Usage is inferable from the sources listed rather than stated.

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