image_search

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

With no annotations, the description carries the transparency burden. It discloses Beta access requirements, the optional reference-image mode, the design-topic behavior, and the result fields. It does not cover rate limits or detailed auth, but it provides substantial behavioral context beyond the schema.

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 front-loaded with the main purpose and keeps usage guidance tight. The keyword line is somewhat redundant but not bloated; overall it is appropriately sized for a 12-parameter tool.

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 complex tool with no output schema and no annotations, the description covers the main invocation patterns, result contents, beta access, and design-mode behavior. It doesn't explain every parameter, but the schema already does; it is complete enough for an agent to select and call the tool correctly.

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 meaning by explaining how query and image_url combine, what topic=design changes in the results, and what html_snippet is for — value beyond the schema's per-property descriptions.

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 a specific verb and resource: 'Find images on the web by text query, and optionally by a reference image.' It also lists concrete return fields and explicitly contrasts with general text web search, distinguishing it from siblings like news_search and video_search.

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?

It gives explicit when-to-use guidance: 'Use this when the user wants pictures, photos, diagrams, screenshots, or visual references — not for general text web search.' It does not name sibling alternatives directly, but the exclusion and use-case list make the choice clear.

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