Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given that the tool has no output schema, no annotations, and four unspecified parameters, the description is incomplete. It does not explain the return format (e.g., list of marker objects with time, label, comment), how to distinguish composition vs. layer markers, or error conditions (e.g., what happens if no composition is found). It provides the bare minimum to understand the action but not enough to use the tool effectively.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.