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

The annotations already mark the tool as non-read-only, idempotent and non-destructive, but the description adds behavior that annotations cannot express: all-or-nothing atomic creation, validation before write, no media generation or approval, and that reusing idempotencyKey on retries returns the original IDs. It doesn't mention permission requirements or limits such as maxItems or the maximum number of scenes, so it falls short of full transparency.

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?

Four short sentences are front-loaded with the action and scope, and each one carries distinct information (modes, validation, exclusions, idempotency). The idempotency and exclusion notes are compressed into single clauses and there is little 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?

For a 10-parameter tool with a nested scenes-shots-assets schema and no output schema, the description covers the essential behavior and return-ID behavior on retries. Gaps remain around the required aspectRatio and workspaceId parameters and the model-default parameters, which are undocumented in both the schema and the description.

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?

With 0% schema description coverage, the description has to carry the parameter meanings. It does explain scenes, shots, media mappings, timing, style, audio tracks, editId (append mode) and idempotencyKey, but it leaves the required aspectRatio, workspaceId and title undocumented, as well as defaultImageModel and defaultVideoModel, so the compensation is only partial.

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 uses a specific verb and resource: 'Atomically create a project with ordered scenes, shots... and existing audio tracks', and clarifies the second mode, appending structure to an existing edit. The word 'atomically' implicitly distinguishes this bulk graph-creation tool from incremental siblings like create_scene, create_shot or add_node, though no sibling is named explicitly.

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?

It states the two operating modes: create a new project, or append structure via editId, and it says 'Validate everything before writing', so the agent knows validation precedes the write. It also rules out out-of-scope work: 'No media generation or approval occurs'. There is no guidance naming alternative tools for those excluded jobs, which keeps it from a 5.

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