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

Adds substantial behavior beyond annotations: the DuckDuckGo HTML source, absence of ads, absence of relevance scores, retry behavior on empty pages, the empty-list note behavior, and per-call pricing with failed calls uncharged. This is exactly the kind of operational context an agent needs.

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?

Four sentences, each carrying useful information: purpose, result characteristics, empty-result behavior, and pricing. It is front-loaded and has no wasted language.

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?

Complete for a two-parameter search tool with an output schema and readOnly/openWorld annotations. The description covers source behavior, failure mode, cost, and result format without needing to restate schema fields.

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 q and limit parameters are already documented by the schema. The description does not add parameter-specific meaning, so the baseline 3 is appropriate.

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: web search via DuckDuckGo's public HTML results page, with ranked titles, URLs, and snippets. It is clear what the tool does, but it does not explicitly differentiate itself from sibling research or search tools.

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 does not say when to use this tool versus alternatives such as deep_research or news_radar. General web-search usage is implied by the name and first sentence, but no selection guidance or exclusions are provided.

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