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

Annotations only declare the safety profile (readOnlyHint false, destructiveHint false), so the description carries the rest and does so well: dedup by case/punctuation-insensitive kind+name with created=false and existing entityId, immediate visibility to collaborators, the full setup applied (moodboard, reference sheet pipeline, production group), and the explicit reassurance of no images generated and no credits spent.

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?

Front-loaded with the core action, then prerequisites, then side effects and returns. Despite being dense, every clause (dedup rule, no-credits note, referenceHandle usage, 20-item cap) conveys information the agent needs to call it correctly.

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 no output schema, the description compensates by documenting the return shape (entityId, referenceHandle) and how to consume it. Prerequisites, side effects, limits, and mutation semantics are all present, leaving nothing an agent needs missing.

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, but the description adds genuine meaning: it documents the kind+name matching semantics that drive dedup and the max-20-per-call limit. It surfaces the entityId/referenceHandle contract rather than restating schema fields.

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 opens with a specific verb and resource ('Create story elements') and enumerates the kinds (characters, places, objects) plus the required name and optional description. This clearly distinguishes it from siblings like list_entities or create_shots, which the description explicitly routes to.

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 prerequisite explicitly ('Call list_entities first') and explains the dedup rule that motivates it. It also tells the agent exactly when the return value matters, pointing to create_shots/update_shot for using the referenceHandle, so both when-to-use and downstream alternatives are covered.

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