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

Adds substantial behavior beyond annotations: it spends credits, dispatches asynchronously and returns before completion, refuses rather than half-applies on invalid multi-scene morph/model input, and warns that bad stills cost the same as good ones. This is exactly the mutation cost, atomicity, and async semantics an agent needs.

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-loads the core action, then layers constraints in dense, non-redundant sentences. It is longer than average, but nearly every clause conveys a distinct operational rule; the morph guidance is verbose but justified by the double-application failure it prevents.

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 10-parameter, credit-spending, async tool with an output schema present (so return values need no explanation), the description covers cost, dispatch/poll lifecycle, readiness prerequisites, and refusal semantics well. It leaves some lower-frequency parameters (idempotency_key, references) undocumented, which is a minor gap.

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 10% across 10 parameters, so the description carries real load: it explains quote, the scenes/all_ready selection mode, morph_into_scene's single-destination rule, and the one-model-per-take constraint. However, storyboard_id, idempotency_key, references, and reference_scenes go unexplained in both description and 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 (animate/film scenes) with precise scope: named scenes, or every ready-still/no-clip scene. An agent can distinguish it from animate_image, generate_clip, and render_storyboard purely from the first sentence.

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?

Gives explicit when-to-use, prerequisites (generate and inspect stills first), follow-up action (poll get_storyboard), and a non-mutating alternative (pass quote to price without filming). Covers when-not implicitly via the still-readiness gate and the multi-scene refusal rules.

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