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

The description asserts 'Exporting the same video twice returns the same clip rather than a second one, and costs nothing', which is a direct claim of idempotent, side-effect-free repeated invocation, while the annotations declare idempotentHint=false. That conflict would mislead an agent deciding whether a retry is safe, and the rule for contradicting annotations applies even though the rest of the description (reference identity with list_media, no cost) is genuinely informative.

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 short sentences, front-loaded with the action and its result, then the interoperability point, then idempotency/cost folded efficiently into one clause. The 'bridge off the board' flourish is minor flavor rather than waste.

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?

An output schema exists, so return values need not be spelled out, yet the description still explains the returned reference's identity and where it can be reused. The remaining gap — that a completed/current cut must exist before exporting (only hinted at by the render_id schema note) — is covered implicitly by 'a finished film'.

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 only 33% (render_id alone is documented) and the description contributes nothing about storyboard_id, video, or the render_id/current-cut distinction. With low coverage the description is expected to compensate for the undocumented parameters, and it does not.

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 states a concrete verb and resource — copying a finished film into the library as an ordinary clip and returning its link — and positions it against the rendering layer ('the bridge off the board'), so an agent can separate it from render_storyboard and list_media without opening a schema.

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?

Usage is implied rather than stated: 'a finished film' and 'the bridge off the board' signal this runs after a render completes, but there is no explicit prerequisite, no when-not-to-use, and no alternative named (e.g., get_download_url vs. export). The downstream consumers (join_clips, create_subject) are mentioned, which is helpful but is about what happens after, not when to pick this tool.

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