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

Annotations indicate readOnlyHint=false and openWorldHint=true, so the description carries the burden of behavioral disclosure. It doesn't state that the operation is irreversible or what changes are made to the image, but it does reveal a cost ($0.05 per image), which is useful contextual behavior. It doesn't mention output format or rate limits.

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 extremely concise, with only two sentences. It front-loads the core action ('Sharpen a blurry photo') and includes the cost as a key decision factor. No wasted words; every bit adds value.

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 simplicity (one parameter, no output schema), the description is fairly complete. It states what it does, the cost, and the input format is in the schema. It could be slightly enhanced by mentioning that the output is a processed image, but that's implied. The lack of alternatives is a minor gap.

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 schema covers 100% of parameters with a clear description of the 'image' parameter (public URL or base64 data URI). The description doesn't add extra meaning beyond what's in the schema, but the schema is sufficient, so the baseline of 3 is appropriate. Cost is mentioned but not parameter-specific.

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 states a specific verb ('Sharpen') and resource ('blurry photo'), clearly indicating the tool's purpose. It distinguishes from siblings like upscale_image and restore_photo by focusing on sharpening rather than resolution enhancement or restoration, though it doesn't explicitly name alternatives.

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 clear context for when to use it (for blurry photos) but doesn't explicitly state when not to use it or mention alternatives. It leaves it to the agent to infer that other tools like upscale_image might be for different kinds of image quality issues.

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