render_video

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

With no annotations, the description carries the full burden. It discloses important behavioral details: sequencer vs 3D scene rendering, playback speed follows scene fps, and the output format constraints (extension must match container, WEBM only OPUS/NONE). It also mentions the return dict. Well above the baseline for a no-annotation mutation-like tool.

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 purpose, then adds context, then parameter details. Efficient and well-structured. Slightly verbose but each sentence adds value. No wasted words.

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 no annotations, 0% schema coverage, and an output schema present, the description covers: purpose, when to use sequencer vs scene, format constraints, parameter semantics, and return value. It is complete for an agent to invoke correctly.

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 0%, so the description must compensate. It does: explains each parameter's meaning (filepath with extension requirement, container enum, quality range, audio_codec with WEBM constraint). This is exactly what the schema lacks.

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+resource: 'Render the scene's frame range to a single video file, with sound.' It clearly distinguishes from siblings render_image (single frame) and render_animation (frame sequence) by describing the sequencer-based assembly path and the final video container output.

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?

Explains when the sequencer path is used ('Sequencer strips are used when there are any') and the alternative ('With an empty sequencer the 3D scene is rendered'). It also implicitly positions this after render_animation. It doesn't explicitly state when to use this vs render_animation or render_image, but the context makes it clear.

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