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

Annotations already declare readOnlyHint true and idempotentHint true, so the description doesn't need to restate safety. It adds valuable behavioral context: result cap of 20 assets, included fields (URLs, captions, tags), and inline thumbnail previews for the first five. This goes beyond the structured annotations.

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?

Two sentences, each earning its place: the first states the core function and resource, the second provides usage context and output details. No redundancy, no filler. Well front-loaded.

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 search tool with four optional parameters and an output schema, the description covers the essential points: asset library, filter dimensions, result limit, and preview behavior. It doesn't explain sorting or default behavior, but those are not necessary given the output schema exists.

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% for all four parameters, each with a clear description. The tool description merely summarizes that you can filter by keyword, category, tags, or file type, which adds no new meaning beyond the schema. Baseline 3 is appropriate.

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: 'Search RealOpen's library of approved affiliate marketing assets.' It enumerates asset types (flyers, social graphics, email banners, etc.), making the tool's scope unmistakable. This clearly differentiates it from sibling tools, which revolve around wallets, proofs, and FAQs.

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 gives an explicit use case: 'Use this when a user asks for existing RealOpen marketing material they can download or share.' It does not mention alternatives or when-not-to-use, but given the sibling toolset, no direct alternative exists, making this guidance sufficient.

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