extract_frame

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

No annotations are supplied, so the description carries the full disclosure burden, and it discloses little: nothing about how the output format is selected, what happens if the timestamp exceeds the media duration, or whether the output path is overwritten. For a file-writing operation with zero annotation coverage this is a meaningful gap.

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?

A single short sentence, front-loaded with the action and resource, with no filler. It is efficient, though the terseness leaves the format-selection rule implicit.

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 and has only three parameters, but with no annotations and no output schema the description should clarify format inference and the default/edge behavior of the timestamp. It is adequate for the happy path but incomplete for correct invocation in ambiguous cases.

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 67% and already documents 'input' and 'timestamp' in seconds. The description adds one useful signal — that PNG/JPG/WebP are the supported output encodings — but it does not state explicitly that the format is inferred from the 'output' extension, which is the key semantic for that parameter.

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 concrete verb plus resource ('grab a single frame') and scopes it with a timestamp and supported image formats, so an agent knows this produces an image still. It does not differentiate itself from the sibling 'thumbnail', which is the tool most likely to be confused with it.

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?

There is no when-to-use or when-not-to-use guidance and no prerequisites mentioned. The sibling 'thumbnail' plausibly overlaps in function, yet the description gives no rule for choosing between them.

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