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

Annotation Contradiction. The description says the tool creates a video and bills the caller in real money, which is a state-changing side effect, while annotations declare readOnlyHint=true. This directly contradicts the annotation and misleads an agent about side effects.

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 compact, efficient sentences carry the essential information: the operation, billing behavior, failure policy, return value, and polling path. No filler or redundant details.

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?

Covers the critical operational details: return type, asynchronous polling via video_status, and cost behavior on success and failure. The schema handles parameter completeness. The annotation contradiction is a notable coherence gap, but the description itself is nearly complete for invoking the tool.

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%, so the schema already documents all parameters including prompt, duration, quality, resolution, aspect_ratio, and quote. The description only restates duration and hints at quote-based pricing, adding no meaningful parameter-level semantics beyond the schema.

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, resource, and scope: 'Create a short video with Grok Imagine (6 or 10 seconds).' It also separates generation from polling by saying the tool returns a video id to check with video_status, which distinguishes it from sibling 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?

Explains the follow-up action explicitly: 'poll it with video_status (free).' It also notes the API-key billing condition. It does not enumerate negative cases or alternatives, but the context is clear enough for an agent to decide when to invoke it.

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