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

Annotations declare openWorldHint=true, indicating the tool may have external side effects or access external data. The description adds the critical cost information (20 MESH/call) and explicitly states it generates exactly one image, which is a behavioral guarantee beyond the annotations. It also includes a legal disclaimer about non-affiliation with xAI, which is unusual and useful for an agent to know before calling. This exceeds the baseline of simply relying on annotations.

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 a single, efficient sentence that front-loads the core action and constraint, then adds cost and disclaimer in a compact manner. There is zero waste—every phrase serves a purpose, from the exact image count to the pricing to the legal note. This is exemplary conciseness.

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 low complexity (1 parameter, no output schema), the description covers the essential facts: what it does, the cost, the provider, and the disclaimer. It lacks details on output format or error handling, but since the output schema is absent and the tool is simple, the description is largely sufficient. The only potential gap is not clarifying the input payload structure (e.g., expecting a 'prompt' field), but the schema's generic description partially mitigates this.

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 has 100% coverage for the single 'input' parameter, which is described as a capability-specific payload. The description adds that the prompt is for image generation, but does not specify the format or structure of the input beyond what the schema says. Since the parameter is an object with nested properties, more detail on what the payload should contain (e.g., 'prompt': 'string') would be helpful, but the schema's generic description already covers some of this, so a 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 states a specific verb ('Generate'), a precise constraint ('exactly 1 higher-quality image'), and the resource ('from a text prompt'), which clearly distinguishes it from sibling tools like grok-image, grok-video-480p, and grok-stt. It also explicitly mentions the provider (xAI) and includes a disclaimer about non-affiliation, which is useful context for an agent deciding between similar image 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?

The description implies usage for image generation from text prompts, but it does not explicitly state when to prefer this over grok-image or other alternatives. It mentions 'higher-quality' which hints at a use case for superior image quality, but there is no clear 'when not to use' or comparison to the sibling tool grok-image. The agent may need to infer the distinction, which is a minor gap.

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