Create a CraftStory 2.0 talking video (photo + audio)

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

Annotations already flag readOnlyHint=false, openWorldHint=true, idempotentHint=false, and destructiveHint=false, and the description adds important non-obvious behavior: credits are charged on create and refunded on failure, generation takes 8-15 minutes, and the agent must poll wait_for_job(model='craftstory-2') then fetch get_job_result. That workflow guidance is valuable and goes beyond the annotations, though it does not cover rate limits or concurrency.

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 description is a single dense paragraph that front-loads the core purpose, then enumerates key options and the post-create workflow. It is efficient with little filler, though the length and semicolon-heavy structure make it slightly dense rather than crisply 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?

For a non-idempotent, credit-charging, multi-minute generation tool with no output schema, the description covers the essential lifecycle: input choices, resolution semantics, cost behavior, and the polling/result workflow. It is nearly complete, missing only explicit success/failure payload details, which are partly handled by the named get_job_result sibling.

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 already high at 91%, so the schema documents most parameters (image_url, image_path, scene_id, avatar_id, gestures, etc.). The description adds meaning by explaining that image_url or image_path provide the photo, scene_id is for a custom avatar scene, resolution is WIDTH_HEIGHT with named portrait/landscape values, and audio_clip_ids are played in order - useful framing that supplements the schema rather than repeating it.

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 opens with a specific verb+resource ('Start a craftstory-2 generation') and immediately specifies the mechanism: a photo of a person speaks audio clips with lip-sync, gestures, and motion. This clearly distinguishes it from the sibling create_minimax_h3_video and create_audio_clip by naming the craftstory-2 model and the photo+audio inputs.

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?

It gives clear context for when to use this tool (photo + audio clips + lip-sync) and points to alternatives for related steps (scene_id/custom avatars via list_avatars, upscale_video for 1080p, preview_cost for cost preview). However, it does not explicitly state when NOT to use it or directly compare against the sibling video generator create_minimax_h3_video.

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