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

Annotations already establish readOnly, idempotent, non-destructive behavior, so the bar is lower; the description still adds real context beyond them — this doubles as the render poll, carries progress and final URLs, and `show` attaches current stills to the answer. These are behavioral traits the annotations cannot express. Return-format details are largely covered by the output schema.

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?

Front-loaded with the verb and the payload list, then the polling guidance, then the `show` semantics — a sensible order with each clause carrying information. It is dense and slightly literary ('a judgement about a picture is made by looking at it'), which costs a little space for a rhetorical aside.

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?

An output schema exists, so the return shape needn't be spelled out, yet the description usefully frames what the answer represents (payload, render progress, final URL) and how `show` changes it. With annotations covering safety and the output schema covering structure, an agent has what it needs to call this correctly; only explicit sibling routing is missing.

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 0%, so the description must carry the load, and it explains `show` meaningfully: it attaches the current stills of the named scenes so a picture can be judged by looking at it. That maps the integer-array parameter to concrete behavior. The required `storyboard_id` is left to inference, though its meaning is evident from the tool name and format:uuid.

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 ('Read') and enumerates the resource's contents concretely — settings, cast, scenes by number with prompts, still/clip state, derived videos, still order, history depth. It never uses the word 'storyboard' in the body, relying on the name/title, and it does not explicitly distinguish itself from list_storyboards. Still, the enumeration is specific enough that an agent knows exactly what it retrieves.

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?

Explicitly declares the polling role: render progress and the finished file URL are on this answer, so 'a caller waiting on work calls this and nothing else.' That is strong when-to-use guidance with an implicit exclusion. It does not name list_storyboards or other read siblings as alternatives, so it stops short of full alternative routing.

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