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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It mentions 'Generate a CDN URL' and 'Supports resizing, format conversion, and quality adjustment,' but lacks details on permissions, rate limits, side effects, or response format. For a tool with no annotation coverage, this is insufficient to inform the agent about behavioral traits.

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 front-loaded and concise: two sentences with zero waste. The first sentence states the core purpose, and the second elaborates on supported transformations. Every sentence earns its place by adding relevant information without redundancy.

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, no annotations, no output schema), the description is incomplete. It covers the purpose and transformation types but lacks usage guidelines, behavioral context, and output details. However, the high schema coverage partially compensates, making it minimally adequate but with clear gaps.

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%, meaning all parameters are documented in the schema. The description adds minimal value beyond this by listing transformation types ('resizing, format conversion, and quality adjustment'), but doesn't provide additional semantics or usage context for parameters. This meets the baseline for high schema coverage.

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 purpose: 'Generate a CDN URL for an image with optional transformations.' It specifies the verb ('Generate'), resource ('CDN URL for an image'), and scope ('optional transformations'). However, it doesn't explicitly differentiate from siblings like 'get_image' or 'upload_image', which might also involve image URLs or transformations.

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 provides no guidance on when to use this tool versus alternatives. It mentions 'optional transformations' but doesn't specify scenarios where this is preferred over other tools like 'get_image' or 'upload_image', nor does it mention prerequisites or exclusions. This leaves the agent without context for tool selection.

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