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

Annotations already mark this as read-only and idempotent, so the bar for additional disclosure is lower. The description adds useful behavior beyond the annotations: the signed URL is valid for an hour, and inline image data is returned only on hosts that display image content. This gives the agent practical expectations about side effects and environment-dependent behavior.

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?

Two sentences carry the precondition, the return behavior, the optional parameter nuance, and the sibling-tool exclusion. Every clause earns its place, and the most important usage condition is front-loaded.

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 annotations, output schema, and the clarity of the description, nothing essential is missing. It covers when to call, what to expect, the optional parameter's effect, the URL validity window, and when to use an alternative tool instead.

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 documents include_image_data directly, and the description clarifies its host-dependent behavior. For the required run_id, the description does not explicitly state that it is the generation run identifier, though this is strongly implied by the tool name and the reference to get_generation_status. With only 50% schema coverage, the description partially compensates but leaves some inference to the agent.

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 what the tool does: returns a signed URL to a provider-rendered mesh preview, optionally including inline image data. It distinguishes itself from get_project_preview and ties to get_generation_status, so an agent can tell it apart from siblings without opening schemas.

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 an explicit precondition ('once get_generation_status reports completed with hasPreview true') and an explicit exclusion ('Do not use for saved logo or coin projects; get_project_preview covers those'). This is model usage guidance with named alternatives and clear conditions.

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