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

No annotations are provided, so the description carries the full burden of behavioral disclosure. The description does not mention what the tool returns (e.g., image URLs, metadata), whether it is read-only, or any side effects. While 'search' implies a read operation, the absence of explicit behavioral details leaves the agent uncertain about output format and potential mutations. The index parameter in the schema hints at multiple results, but the description fails to state this behavior.

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 (two sentences) and front-loaded with the core purpose, followed immediately by a sharp usage criterion. Every clause earns its place; no filler, no repetition of schema details. The 'ONLY use' constraint is bolded for emphasis, aiding quick scanning.

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 tool with two simple parameters and no output schema, the description is expected to explain what the tool returns and any limitations. It does not mention the structure of results (e.g., list of image URLs, thumbnail sizes), how many results are returned, or how the 'index' parameter interacts with results (beyond schema's minimal note). This gap forces the agent to guess about the return format, which is critical for using the tool's output. The description also omits any constraints like licensing or content policy. Given the absence of annotations and output schema, this is a significant incompleteness.

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 coverage is 100%, so the baseline is 3. The description adds value beyond the schema by providing concrete example query terms ('espresso', 'discount banner', 'sunset'), which help the agent formulate effective queries. It also restates the purpose of the keyword query in context ('for message templates or cards'). This enriches the schema's basic parameter descriptions without redundant repetition.

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?

Description clearly states it searches for stock photos/graphics for message templates or cards, with a specific verb and resource. It also distinguishes the intended use from general search by mentioning the specific context, which helps separate it from sibling tools like search_documentation.

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 states the only conditions under which to use the tool ('ONLY use this tool when the user specifically requests a card/carousel example or when actively creating a rich card template'). This provides clear when-to-use guidance and implicitly excludes other scenarios, leaving no ambiguity about alternatives.

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