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

Annotations already flag readOnlyHint=false and openWorldHint=true, so the mutation and open-world nature are covered. The description adds the non-obvious prohibition on videoType (which the permissive schema would otherwise allow), but says nothing about this being an async/long-running generation whose output must be fetched elsewhere, nor about cost or image-quality requirements.

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 short sentences with zero filler: the generation action first, then the critical constraint. Nothing to trim and nothing buried.

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 video generation tool with no output schema and seven parameters, the description should say what the call returns and how to retrieve the finished video (the sibling nexscope_media_task_result suggests an async task model). That retrieval path is the main thing an agent needs and it is absent, though the required-input shape is otherwise well covered.

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 100%, so the baseline is 3; the description earns an increment by documenting a constraint the schema does not express at all — that videoType must never be included because the model is fixed. Its mention of 1-9 images duplicates minItems/maxItems already present in the schema and adds nothing.

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 (generate) plus resource (MiniMax H3 Lite video) and the input form (1-9 reference images). It does not name or contrast with the near-identical sibling nexscope_minimax_h3_video_generation, nor with other video models (kling, seedance, wan), so the agent must infer the difference from the model name alone.

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 gives one hard usage rule ('model is fixed, so videoType must not be supplied'), which is genuinely useful because the schema allows additionalProperties. It offers no guidance on when to pick this Lite model versus nexscope_minimax_h3_video_generation or another video tool, and no prerequisites about the reference images.

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