image_search

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It mentions 'No API key' and backend choices, but does not explicitly state that this is a read-only operation, whether results are scraped, how errors are surfaced, or if there are rate limits. The 'search' wording implies non-destructive behavior, but an agent gains little insight beyond a typical search 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?

The description is compact and well-structured: a one-line purpose statement followed by a tabulated args list. Every line serves a purpose, and the format is easy to scan. It earns its place given the empty schema descriptions, though a shorter phrasing could have been slightly tighter.

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 read-only search tool with an output schema present, the description covers invocation essentials: purpose, all parameters with allowed values, authentication status (no API key), and backend selection. It omits only explicit sibling-routing guidance and behavioral caveats, which are minor because the output schema already addresses return values.

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 0%, so the description compensates by documenting all five parameters: query, max_results with range constraint, region with examples, safesearch with allowed values, and backend with 'auto' plus specific engines. This adds meaningful value beyond the bare schema defaults, though it could further explain the region's effect and safesearch semantics.

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 opens with 'Image search via DDGS (DuckDuckGo/Bing image backends)', which names the operation (search) and resource (images) and explicitly distinguishes it from siblings like news_search and video_search. The specific backends further differentiate it from web_search, leaving no ambiguity about what the tool does.

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 states 'No API key' and lists backend options, implying this is the image-specific search tool among the siblings. However, it never explicitly says 'use this when you need images' or contrasts it with web_search, news_search, etc. The usage context is implied by the resource and sibling names rather than directly stated.

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