still_grab

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

With no annotations, the description carries the full burden for behavioral disclosure. It explains that the tool requires the Color page and describes the frame_source parameter behavior for all_clips. However, it does not disclose whether the operation is destructive, what gets modified (e.g., creates a still in a gallery), or any side effects. The information is partially helpful but incomplete.

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 extremely concise, consisting of three short sentences. The main action is front-loaded, and every sentence adds value: what the tool does, parameter behavior, and a prerequisite. There is no wasted text.

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 description lacks information about return values or success/failure behavior, which is important for a tool that creates an artifact (a still). The definition of 'current clip' is not clarified, and error cases are not mentioned. Given the tool's moderate complexity and absence of an output schema, the description is incomplete.

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?

The input schema has 0% description coverage, so the description must compensate. It explains the frame_source parameter's meaning when all_clips is true (1=first frame, 2=middle frame) and implies that all_clips controls whether to process all clips or just the current one. This adds significant value beyond the schema, though frame_source when all_clips is false is not explicitly addressed.

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 grabs a gallery still, specifying two modes: current clip or all clips on the timeline. This is distinct from sibling tools like still_list (list stills) or still_export (export stills), and the verb 'grab' is specific and unambiguous.

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 mentions a prerequisite ('Requires the Color page'), which provides important context for usage. However, it does not explicitly state when to use this tool versus alternatives, nor does it provide exclusions or when-not-to-use guidance. The implied usage is clear but not fully elaborated.

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