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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and closed-world scope, so the safety profile is covered elsewhere. The description adds one real behavioural fact beyond that — 'Cost: Free' — which helps an agent weigh it against costlier operations, but says nothing about whether the canvas persists, how selection state interacts with canvas_select, or the effect of opening without a video.

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 front-loaded sentence plus a short cost tag, with no filler. The only weakness is the loose phrasing 'their videos', whose antecedent is unclear on a first read.

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, rich annotations, and a fully described single optional parameter, the description only needs to convey purpose, the two modes, and cost — all of which it does. Nothing an agent needs to call it correctly is missing.

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% and the single parameter already documents the omit-behaviour, so the baseline is 3. The description reinforces the semantics by mapping the two modes explicitly (all videos vs. one video with its timeline), which confirms what omitting video_id actually yields rather than merely restating the field.

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 states a concrete verb and resource ('Shows the Clypmint canvas') and spells out the two modes: the video library, or a single video with its timeline. That is specific enough to picture the result, though it never contrasts itself with near-neighbours like canvas_live or get_screenshot.

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?

'to watch your changes and select layers' gives an implied use case (visual verification after edits, picking layers), which is genuine context for when to reach for this tool. However, there are no exclusions and no alternatives named, so an agent facing canvas_live, canvas_select, get_timeline or get_screenshot has to guess which one to call.

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