item_set_composite

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

No annotations are provided, so the description carries full burden. It only says 'Set composite mode and/or opacity' without disclosing side effects, reversibility, or permissions. It does not mention that this is a mutating operation with potentially persistent effects, nor any constraints on when it works (e.g., only on video tracks).

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 action and resource. Every word earns its place, with no redundancy or filler.

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 has 5 parameters with full schema coverage, but no annotations and an unknown output schema. The description is adequate for a basic setter tool, yet it lacks behavioral context such as prerequisites (item must exist), range validation beyond schema, or what happens on failure. It is complete enough for simple usage but misses deeper context.

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 100%; the schema already documents mode, opacity, item_name, track_type, and track_index. The description adds the 'and/or' semantics (can set one or both) but otherwise provides no additional parameter detail beyond what the schema already includes.

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 action (Set), the resource (composite mode and/or opacity), and the target (timeline item). It distinguishes itself from sibling tools like item_set_property or item_set_transform by specifying composite mode and opacity specifically.

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?

Usage is implied by the name and description: use this tool to set composite mode or opacity on an item. However, it does not explicitly state when to choose this over alternatives like item_set_property, nor does it mention limitations such as video-only applicability or track type restrictions.

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