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

The description discloses internal behavior: it samples frames, measures subject location and detail survival, and decides between crop and fit (with blurred backdrop). It mentions 'writing the frame' indicating a mutation, and notes it returns the project identity. While annotations provide no hints (all false), the description carries the burden and does so well, though it doesn't cover side effects or reversibility.

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 long but front-loaded with scope and purpose ('PROJECT-SCOPED', 'THE tool'). Every sentence adds value—explaining the measurement logic, mode behavior, and the truncation complaint. It could be trimmed slightly, but the structure is logical and efficient.

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?

With no output schema, the description should clarify the return value. It says 'returns the project identity with its result' and 'Read what it reports and repeat THAT,' but the 'result' and 'THAT' are vague. It doesn't specify the output format or error conditions, leaving an agent uncertain about how to interpret and act on the result.

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 only 33% (project_id has a description), but the description compensates by explaining mode's behavior ('auto' default, crop vs pad) and implicitly clarifies ratio via the title. It adds meaning beyond the enum for mode, and reinforces project_id's immutability. Ratio is not directly explained but is obvious from context.

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 explicitly states it is 'THE tool for make it 9:16 / vertical / for TikTok' and emphasizes 'PROJECT-SCOPED', clearly distinguishing it from siblings like add_aspect_shift or set_frame. It names the specific verb (reframe) and the resource (project video), leaving no ambiguity about its function.

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?

It gives explicit usage guidance: 'Pass mode explicitly to force one' and instructs the agent to 'Read what it reports and repeat THAT.' It positions itself as the definitive tool for vertical/square conversion, implying when to use it, though it doesn't explicitly list alternatives or when not to use it. The context is sufficient for an agent to select it correctly.

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