DuckDuckGo Search

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

The annotations already declare readOnlyHint, openWorldHint, and destructiveHint, so the safety profile is covered elsewhere. The description does add the non-obvious cost model ('1 credit per call'), which is genuinely useful. It says nothing about result counts per page, how deep pagination goes, or whether results are cached or rate-limited.

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?

Three short sentences, front-loaded with the action and resource, no filler. Minor redundancy in restating the tool name before 'Query DuckDuckGo', but nothing that costs the reader real effort.

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?

For a five-parameter, fully documented read-only search tool with no output schema, the description covers the essentials plus cost. It is still thin on result shape and pagination limits, which an agent must know to iterate correctly, so it is adequate but not complete.

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 schema already explains gl, hl, page, query, and fields in adequate detail. The description only alludes to 'region and language' without adding format, defaults, or interaction semantics beyond that. Baseline 3 applies when the schema carries the parameter burden.

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 uses a specific verb-and-resource pair ('Query DuckDuckGo via API and retrieve structured organic results') and names the engine, which in practice separates it from google_search, bing_search, and brave_search. It stops short of any explicit contrast with those siblings.

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?

There is no guidance on when to pick this engine over the many sibling search tools, nor on prerequisites or exclusions. The only decision-relevant fact offered is the credit cost, which speaks to budget rather than to selection.

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