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

Annotations already declare non-destructive, non-idempotent, non-open-world, so the safety profile is covered. The description adds genuinely new behavior: no credit cost and a single undo step reversible via undo_storyboard. That is meaningful beyond the structured hints.

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?

Three tight sentences, front-loaded with the action, then follow-up id usage, then the cost/undo facts. The 'brief prints it with the [id]' phrasing is slightly awkward but carries real information about the return value, so it 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 an output schema present and annotations covering safety, the description only needs to add cost, reversibility, and follow-up tooling — all of which it does. Remaining gaps (size limits, distinction from add_storyboard_note) are minor but real.

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 0%, so the description carries the burden. It conveys the size enum meaning ('title or body text') and the near_scene placement, but says nothing about the 500-character limit on text or about storyboard_id beyond the implied 'film's canvas'. Partial compensation for a fully undocumented schema.

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?

States a specific verb and resource: putting a text element on a film's canvas, with the size variants (title/body) and optional scene placement. It's clearly distinct from update_storyboard_annotation and remove_storyboard_annotation, which it references as follow-ups. It does not, however, distinguish itself from the sibling add_storyboard_note, which an agent would plausibly confuse with this.

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?

'Optionally near a scene' and the mention of update/remove annotation hint at usage, but there is no explicit when-to-use versus add_storyboard_note or add_captions. The recovery path ('undo_storyboard takes it back') is useful context but is not usage guidance for choosing the tool.

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