Generate a cover image

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

The description goes well beyond annotations by disclosing: generation costs credits, is not idempotent, takes longer than other tools, requires an API key, produces a public non-deletable URL, and yields varying results. This adds critical context for a state-changing tool with financial implications.

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 yet information-dense. Each sentence adds value: purpose, usage, side effects, and limitations. No redundant phrases or filler—perfectly structured for quick comprehension.

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 generative, cost-incurring tool with no output schema, the description covers all essential context: output (public URL), prerequisites (API key), side effects (cost, non-deletion, variability), and performance expectations. Very complete for agent decision-making.

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% with detailed descriptions for both parameters (prompt and size). The description adds no parameter-specific information beyond what the schema already provides, so the baseline of 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 clearly states the tool's function: 'Generate an image from a text prompt with AI, upload it to the Misar.Blog CDN, and return its public URL for use as cover_image_url when publishing.' It names specific verbs and the resource, and explicitly contrasts with upload_image, distinguishing it from sibling tools.

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 when-to-use guidance: 'Use it when no artwork exists yet; use upload_image for a file the user already has.' It also notes cost implications and non-idempotency, helping the agent decide based on context.

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