image_search

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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false. The description adds substantial behavioral context beyond the schema: per-provider result limits (up to 200 on Brave, 10 on Google), a 30-minute freshness window, and provider-specific filter handling. This goes well beyond the baseline.

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 four sentences, front-loaded with the core purpose. Each sentence adds distinct value: filter capabilities, result limits, usage guidance, and freshness. No redundant or filler 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?

For a tool with 11 parameters, 7 enums, and an output schema, the description sufficiently covers the tool's scope, selection criteria, provider differences, and freshness. Parameter details are already fully captured in the schema, and the output schema handles return structure, so no critical gaps remain.

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%, and each parameter's schema description already includes provider-specific caveats (e.g., Brave ignores size/type/color). The tool description only mentions filter categories generically without adding new syntax or details not present in the schema. Baseline 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 clearly identifies the tool's action ('Find images on the web') and resource ('images'), with a specific verb and scope. It also distinguishes itself from sibling tools by noting it is 'Best for finding visual references or assets' and explicitly directing text-content users to web_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?

Provides explicit usage context: 'Best for finding visual references or assets' and a clear alternative: 'use web_search if you need text content from pages that contain images.' Also explains provider-specific result limits, setting expectations for when to use which provider.

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