vibeside_capture_video_frame

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

No annotations are provided, so the description carries the full disclosure burden. It helpfully states the return payload is base64 with dimensions and a timestamp, but omits that the operation is read-only/non-destructive and says nothing about failure cases such as canvas tainting on cross-origin video or a video that has not yet loaded.

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?

A single well-formed sentence that front-loads the action and resource and packs in output format, return encoding, and metadata with zero filler.

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 no output schema, the description correctly specifies the return content (base64 PNG/JPEG plus dimensions and timestamp), and the required selector is documented in the schema. It is nearly complete, but the absence of any note about capture preconditions or failure modes leaves a small gap for a capture tool with no annotations.

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 100%, so both 'format', 'quality', and 'selector' are already fully documented, including defaults and ranges. The description restates the output formats but adds no semantics beyond what the schema provides, making the baseline 3 appropriate.

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 ('capture'), a precise resource ('current frame of an HTML5 video element'), and the output form (base64 PNG or JPEG). This clearly delimits it from the sibling vibeside_screenshot, which captures the viewport rather than a video element's frame.

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?

Usage is only implied by the phrase 'HTML5 video element' — an agent can infer it applies when a video is present, but the description names no alternatives, no preconditions (video loaded, playing, same-origin), and no when-not-to-use guidance such as preferring vibeside_screenshot for non-video content.

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