Paint: undo / redo

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

Annotations already flag destructiveHint=true and non-idempotent, so safety is covered. The description adds real value beyond them by disclosing the step granularity model ('each drawing operation is one step', 'a paint_ops batch rolls back one step per op') and by noting that the 'steps' action is non-mutating, which nuances the blanket destructive hint.

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 dense sentences with the purpose front-loaded, then granularity, then the non-mutating tip — every clause earns its place. Minor awkwardness in the trailing 'action:'steps'' phrasing keeps it from being exemplary.

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 4 params (1 required), no output schema, and annotations already carrying the safety profile, the description covers what an agent needs: what it mutates, step granularity, and the non-mutating inspection action. Only the behavior at stack boundaries is left unstated, a minor omission.

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 75% and it already documents steps, canvas, and preview. The description adds meaning the schema lacks: how steps are counted for paint_ops batches and the read-only semantics of the 'steps' action. No per-parameter syntax is added, but the semantic gap around step counting is filled.

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+resource ('Roll a canvas back or forward') that maps cleanly to undo/redo, and the title confirms the scope. It does not explicitly contrast itself with any sibling, but no sibling duplicates this function, so ambiguity is low.

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?

Gives one concrete usage rule for the 'steps' action ('see the stack without changing anything'), which is genuinely helpful. However, it never explains when to choose undo vs redo vs steps, nor what happens when the stack is exhausted — usage is implied rather than stated.

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