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

The description discloses key behavioral traits beyond annotations: it returns a public URL, consumes credits, and has an async timeout behavior where 'the job continues running' and can be retrieved later via jobId. This is valuable context that annotations do not provide, and it does not contradict the readOnlyHint=false annotation.

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 three sentences, each serving a distinct purpose: what it does, when to use it, and important async/cost behavior. It is front-loaded with the core function and conveys substantial information without fluff.

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 complexity (7 parameters, external API, async behavior, costs, and output schema), the description covers purpose, usage scenarios, exclusions, cost implications, and timeout behavior. It also points to the jobId retrieval mechanism, making it complete for an agent to select and invoke 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?

The input schema has 100% coverage with descriptions for all parameters, so the baseline is 3. The description adds some context about the jobId in the response (related to pollTimeoutMs) but does not significantly elaborate on parameter meanings beyond the schema. It adequately meets the baseline without adding much extra.

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 states the tool's function: 'Generate an AI image via kie.ai and return its public R2 URL.' It specifies the resource (AI image via kie.ai) and the output (public R2 URL), and distinguishes from siblings by noting it 'does NOT attach to a post by itself,' setting it apart from tools like generate_post_cover.

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?

Explicit usage context is provided: 'Use to mint reusable URLs for content blocks (image, gallery), product photos, or any field that takes an image URL.' It also states what it does not do ('does NOT attach to a post by itself') and mentions cost implications ('Costs credits (see list_image_models)'), guiding when to use and when to consider alternatives.

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