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

Annotations indicate readOnlyHint=false and destructiveHint=false, but the description adds valuable behavioral context: cost (17 credits per second), output format (R2-hosted URL), and the outpainting/cropping mechanism. It also clarifies that the source must be a public URL. No contradiction with annotations; this is a solid disclosure of operation 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?

The description is three sentences, front-loaded with the primary action, and every sentence adds meaningful info: operation, required inputs, optional prompt with example, cost, and return format. There is no fluff or redundancy, making it highly efficient and well-structured.

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?

The tool has no output schema, so the description's mention of 'Returns the reframed video URL (R2-hosted)' fills that gap. It covers purpose, inputs, optional parameter, cost, and output. It could additionally note potential processing time or failure modes, but the provided information is sufficient for an agent to decide to invoke the tool. Sibling tools are similar but not referenced, yet the context is complete for a typical use case.

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 three parameters. The description adds marginal value by giving an example for reframePrompt and emphasizing videoUrl must be public, but this is largely redundant. Baseline 3 applies because the schema does the heavy lifting; the description does not significantly enhance parameter understanding.

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: 'Reframes a video to a new aspect ratio by intelligently outpainting/cropping the edges.' It uses a specific verb ('reframes') and resource ('video'), and the mention of 'video' distinguishes it from the sibling reframe_image tool. The title also adds model context (Luma Ray 2 Flash), reinforcing the specific operation.

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 clear context for when to use the tool: to change a video's aspect ratio via outpainting/cropping. It specifies required inputs (public videoUrl and reframeAspectRatio) and optional reframePrompt. However, it does not explicitly compare to alternatives or state exclusions (e.g., 'use reframe_image for images'), though sibling tooling implies this. This is a minor gap, so 4 is appropriate.

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