Create a composition

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

Annotations only indicate that the tool is not read-only and not open-world. The description adds useful behavioral context: creating also opens the comp in the timeline, and backgroundColor is purely a preview convenience and will not appear in rendered output. No contradiction with annotations.

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?

Two sentences with no filler: the first states the primary action and side effect, the second delivers the most important non-obvious caveat. Every sentence earns its place.

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?

With all parameters documented in the schema and the key rendering caveat explained, the description is sufficient for a competent agent to invoke the tool correctly. It does not state the return value, and there is no output schema, but that is a minor gap for a creation tool.

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 100%, so the baseline is 3. The description adds meaningful semantic value beyond the schema for backgroundColor—that it is preview-only and needs a solid layer to appear in renders—which the schema's format-focused description does not convey.

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 states a specific verb ('create') and resource ('new composition') and adds a concrete side effect—opening it in the timeline. This clearly distinguishes the tool from sibling tools that list, inspect, or modify existing comps.

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 word 'new' implies this tool should be used for creating comps rather than modifying existing ones, but the description offers no explicit when-to-use guidance or named alternatives. The agent must infer the appropriate context from the verb alone.

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