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

Annotations already mark readOnlyHint and openWorldHint, so safety/read semantics are covered by structured data. The description adds relevant behavioral context: results are in DuckDuckGo's own ranking order and capped at 8 suggestions by the service. It does not contradict the annotations, but does not add much beyond the schema on limits.

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?

Two sentences, front-loaded with what the tool returns, follow-up with usage hint and constraints. No wasted words. Could be slightly denser by moving the max-8 detail out (already in schema).

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 simple 3-param autocomplete tool with a full output schema and annotations, the description covers purpose, intended use, and key constraints. It lacks only alternative routing guidance, which is minor given the clear 'suggest' identity among ~2000 tools.

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 params (q, count, region) are fully documented in the schema. The description adds only a marginal example of region (us-en, de-de) and repeats the max-8 limit, both already in the schema. Baseline 3 when the schema does the heavy lifting.

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 (returns autocomplete completions), a specific resource (DuckDuckGo search-box autocomplete), and the exact input type (query prefix). Distinct from duckduckgo_search and other suggest tools due to the explicit 'search-box autocomplete' framing and named ranking order.

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 says 'Use for keyword ideas', which clarifies the intended use case. However, it does not name sibling tools (e.g. duckduckgo_search) or state when NOT to use it. For a suggest endpoint, the target scenario is clear, but alternative routing is unstated.

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