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

Annotations only mark it non-read-only and non-destructive; the description adds the critical behavioral facts an agent needs — it costs credits per frame, dry_run previews the price, rerender_from re-renders for free, and a mandatory user-facing disclaimer must be conveyed. This is rich disclosure beyond the structured fields.

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?

The core action and cost warning are front-loaded, and each sentence carries distinct information (preset availability, cost, dry_run, rerender, disclaimer, polling). It is dense, with the embedded quoted disclaimer text making it feel cramped, but nothing is redundant.

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 credit-consuming mutation tool with no output schema, the description covers cost, the preview path, the free re-render path, the compliance disclaimer, and completion polling. Only minor gaps remain around expected return shape and what the job produces.

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 71%, and the description meaningfully extends it: dry_run as a cost preview, rerender_from as a free re-render path using a finished job_id, and ausnahmen as object ids that stay sharp (rerender only). The 'e.g. exceptions' phrasing is slightly muddled but the semantics are conveyed.

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 ('Run a video VFX preset on a whole clip') and names the live preset, so the agent knows exactly what executes. It differentiates from siblings by pointing to lab_vfx_preset_status for polling and away from generic lab_vfx tools.

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 clear workflow guidance: call with dry_run=true first to check price, use rerender_from for a free re-render with different settings, and poll lab_vfx_preset_status until done|failed. It does not explicitly state when not to use this tool, but the cost and re-render conditions are well framed.

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