Video storyboard

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds real behavioral context the annotations do not: output is ONE composited grid image rather than N images, tiles carry timestamps, and live/non-seekable videos are sampled while playing — a meaningful side effect (playback is driven).

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 tight sentences with the core behavior front-loaded and the live-video caveat as a follow-up. Every clause earns its place; no restatement of the title.

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 explains the return shape (one stamped grid image) and covers the tricky edge case of non-seekable video. It does not mention cost/latency for large counts or what happens if the range exceeds the video length, which are minor remaining gaps for a 7-param optional-only tool.

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 baseline is 3. The description adds semantics the schema lacks: sampling is *even* across the range (not arbitrary), and the output is a single grid, which explains why columns and tileWidth exist as layout controls rather than per-frame properties.

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 and resource: samples N frames evenly across a time range and returns them as one grid image with timestamped tiles. The phrase 'see a whole stretch of video at once' implicitly distinguishes it from single-frame siblings like video_frame and from video_watch, so an agent can route between them without opening schemas.

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 implied by 'so you can see a whole stretch of video at once,' which signals the overview/contact-sheet use case. But no sibling is named and there is no explicit when-not guidance (e.g. use video_frame for a single precise frame, video_watch for temporal analysis).

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