search_images

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, and it delivers. It reveals the exact result structure, notes engine-specific field availability (e.g., Google path fills only a subset), and states that results are in engine relevance order. This goes beyond basic expectations, though it does not cover error handling or rate 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?

The description is concise, front-loaded with the primary action, and every sentence adds value. It efficiently packs important behavioral details (result keys, engine variations, empty field conventions) without verbosity or repetition of schema content.

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?

Given the tool's simplicity (3 params, one required), an existing output schema, and clear return-value documentation in the description, the contextual information is complete. It covers what the tool does, what results look like, how engines differ, and the ordering, leaving minimal room for ambiguity.

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?

The input schema already provides detailed descriptions and defaults for all three parameters (query, engine, max_images), achieving 100% schema description coverage. The tool description adds no additional parameter-specific semantics, but the schema alone is sufficient, so the baseline score of 3 applies.

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 ('Search') and resource ('images'), clearly distinguishing it from sibling tools like search_youtube or search_books. It explicitly states it returns a list of result objects with image URLs and metadata, making the tool's function unmistakable.

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 clearly implies when to use this tool (when you need images from the web) and the context is unmistakable given sibling search tools for other media types. It does not explicitly mention alternatives or exclusions, but the purpose is so concrete that no additional guidance is needed.

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