Extract frame

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

No annotations are provided, so the description must carry the transparency burden. It states the output (PNG frame) and the input (timestamp), which is core behavior, but it does not explicitly declare read-only status or any prerequisites/error behavior. For a simple extraction, this is moderately transparent.

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, concise sentence that is front-loaded with the main action and purpose. Every word contributes meaning, with no filler or redundancy.

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 is simple, but the description is incomplete for an agent. It does not explain the 'asset' parameter, the units of atSec, or any constraints on the timestamp. With no output schema or annotations, these gaps matter for correct invocation.

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 explain the parameters. It only vaguely references 'timestamp' (which maps to the atSec parameter), but it does not clarify what 'asset' refers to or the units of the timestamp. This leaves the required parameter under-specified.

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 gives a specific verb ('Extract') and resource ('a single PNG frame from a video at a timestamp'), and even adds the use case 'visually QA a render'. This clearly distinguishes it from sibling tools like render_video or generate_video.

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: 'use it to visually QA a render'. This tells the agent when to employ the tool, though it does not explicitly mention alternatives or when not to use it, which prevents a 5.

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