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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint=false, so the safety profile is covered elsewhere. The description adds only the pricing fact ('Cost: Free') and says nothing about how the refresh affects existing canvas state, latency, or what a caller observes.

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 short sentences with no filler, and the caller restriction is front-loaded ahead of the cost note. It is efficiently written, though the brevity reflects under-specification rather than tight editing of rich content.

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 six parameters, an output schema, and rich annotations, an agent still cannot tell from the description what a refresh does or what at/strip/film/package control. The caller restriction and free-cost note are the only context given for a tool whose semantics remain opaque.

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 the schema technically documents all six parameters, which sets the baseline at 3. The description adds no meaning beyond that, and the schema's own parameter text is terse to the point of being cryptic ('Film.', 'Package.'), which the description could have clarified but does not.

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 itself never states a verb or resource; the only purpose signal comes from the title 'Refresh the canvas' paired with the name canvas_live. That points at re-rendering a live canvas, but the text does not say what is refreshed or how it differs from siblings such as open_canvas, canvas_select, or get_timeline.

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?

'Only the canvas app calls this' is a real when-to-use constraint that steers a general agent away from invoking it, which is more than most definitions offer. It names no alternative tool and gives no condition under which an agent legitimately should call it, so the guidance stays implicit.

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