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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world, so the safety profile is covered. The description adds the return behavior ('return its link'), which is useful given there is no output schema, but says nothing about preview format, size limits, or failure modes for invalid/hotlink-protected URLs.

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?

One sentence, front-loaded with the action and constrained by the host scope, with zero filler.

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 single-parameter, read-only viewer with full schema coverage and rich annotations, the description tells the agent what it gets back and what inputs are valid. Only error/edge-case behavior is unstated, a minor gap at this complexity.

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 the single image_url parameter, so baseline is 3. The description does reinforce the accepted host scope, but adds no format or validation detail beyond the schema's example URL.

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?

States a specific verb and resource ('Show a preview of an image') and scopes it to HalalGen-hosted images, which separates it from generate_image, edit_image, and upscale_image. It stops short of naming an alternative sibling such as fetch, so sibling differentiation is only implicit.

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 domain restriction ('hosted by halalgen.ai or cdn.halalgen.ai') implies when the tool is valid, but there is no explicit when-to-use versus fetch or list_generations, and no statement of what happens with an external URL.

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