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

Annotations already communicate mutation, destructiveness, and idempotency. The description adds valuable beyond-annotation context: the operation is paid, changing selection or FPS creates a new export rather than modifying the old one, and source motion is never regenerated. No contradiction with the annotations found.

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 tight sentences with no filler. The most important information—paid export, existing asset, and the critical behavioral warning—is front-loaded.

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?

Given the rich self-documenting schema and presence of an output schema, the description covers the essential high-level context: payment authorization and the key behavioral pitfall. It could mention the quote-first workflow, but an agent can still invoke the tool correctly with the information provided.

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?

The description adds useful meaning around quote_id/max_credits ('approved') and the selection/FPS side effects, but the schema already documents most parameters in detail. With 50% schema coverage, the description only partially compensates and leaves idempotency_key and request-structure semantics to the 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?

The description names a specific action ('Start a paid export'), a specific resource ('existing video asset'), and the required payment precondition ('approved quote_id or max_credits'). This clearly distinguishes it from source-generation tools like generate_animation and from quote/get/cancel export siblings.

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?

The description implies when the tool is appropriate: only for paid exports from an already-existing video asset. However, it never explicitly points to quote_animation_export for obtaining a quote, nor does it state what to do when no quote or credits are available. It provides context but no explicit alternatives or exclusions.

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