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

With no annotations, the description does substantial work: it discloses that the operation is undoable, that it stages as a scenario then applies it, that it clears the draft path, and that shot drafting is metered in credits unless the owner supplies their own Anthropic key. That is exactly the kind of safety/cost context annotations would otherwise carry. It stops short of describing failure behavior (e.g. what happens on a version mismatch) or what identifiers are returned.

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 dense sentences, front-loaded with the primary effect, and the parenthetical on staging/applying is efficient rather than wasteful. The second sentence is long but earns its length by covering cost and output shape.

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 high-impact, multi-entity, irreversible-looking bulk operation with no annotations and no output schema, the description covers cost, atomicity and cleanup well but omits expectedVersion semantics and any indication of what the caller gets back (scenario id, scene ids, counts). Those are the remaining gaps an agent would need before invoking.

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 0%, so the description must compensate. It explains draftShots well (default true, downstream effect of producing shots and one placeholder per shot, credit cost), but projectId is only implicit and expectedVersion — the non-obvious optimistic-concurrency token and the reason it is required — is never explained, leaving a caller guessing what value to supply.

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 names a specific verb+resource transformation: turning the accepted storyline path into scenes, placeholders, prompts and timeline items, and it explicitly distinguishes itself from the sibling primitives scene.create, timeline.add_placeholder and scenario.apply_to_timeline by doing all of them in one step. It also clarifies that it clears the draft path afterward, which no sibling does.

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 accepted storyline path' implies the precondition (a path must have been accepted via storyline.pick), but the description never states when to use this instead of scenario.apply_to_timeline or manually creating scenes. It does flag the draftShots default of true and the cost implication, which is useful context for selecting the call, but there are no explicit exclusions or alternatives.

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