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

Annotations already cover safety (readOnly, idempotent, non-destructive, closed world) and the description does not contradict them. It adds non-obvious context about the payload: versions rendered as small films, the recipes each needs, what « Ajouter au film » sends, and a one-line verdict — useful for anticipating output with no output schema present.

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, no filler, and the constraint plus sibling routing are front-loaded ahead of the payload summary. The second sentence is dense and jargon-heavy ('the recipes they need', 'its verdict in one line'), costing a little immediate legibility.

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 four parameters and no output schema, the description must carry the return-shape burden; it does so only vaguely in domain terms. Annotations cover the safety profile, so nothing critical is missing, but the payload contents and the meaning of 'Cutscene's window' remain underspecified.

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% with per-parameter descriptions, including how `at` positions the piece and how `name` selects the film. The description only gestures at « Ajouter au film » (the `at` semantics) without adding format or default detail beyond the schema, so baseline 3 applies.

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?

Names the resource (a piece) and pins its narrow scope — the payload for Cutscene's window specifically — and explicitly routes general reads to get_piece. No explicit verb ('returns'/'gets') and the second sentence is domain jargon, but an agent can still tell what it fetches and how it differs from the sibling.

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?

States the exclusivity condition ('For Cutscene's window only') and names the preferred alternative ('to read a piece, prefer get_piece'). Both the when and the when-not are explicit.

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