render_html_video

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

The description adds substantial behavioral detail beyond annotations: frame-by-frame capture with no dropped frames/quality loss, specific codecs and formats, resolution/fps ranges, output written to the bundle directory, and dependencies (Playwright + ffmpeg). It does not contradict the annotations.

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 two brief paragraphs, front-loaded with the core purpose. Every sentence adds value: purpose, use case, capture/encode behavior, output location, and dependency note. No waste.

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?

With an output schema present, the description need not explain return values. It covers the main operational aspects: self-contained HTML input, output formats, quality, resolution/fps limits, file location, and runtime dependencies. This is sufficient for a tool of moderate complexity.

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 0%, so the description must compensate. It adds meaning for format (mp4/gif/webm), fps range (5-60), resolution (up to 4K), and output path. It does not explicitly explain duration_s, but the parameter name and default make it reasonably clear.

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: 'Render an HTML document (CSS / JS / canvas animation) to mp4/gif/webm.' This clearly distinguishes it from sibling tools like analyze_video or get_video_gif, which focus on existing videos rather than generating new ones from HTML.

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 explicitly says 'Use this to export a self-contained animated HTML page (e.g. one you just designed) as a shareable clip,' giving clear context. It does not explicitly list when not to use it or name alternatives, but the use case is precise enough.

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