undo

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

With no annotations, the description carries the full burden, and it does disclose granularity -- a single most-recent action, scoped to the active sprite. It stops short of the traits that matter for an undo: whether structural operations (frames, layers, groups) are also covered by 'editing tool call or transaction,' how deep the undo stack goes, and what happens when there is nothing left to undo.

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?

One sentence, no filler, with the scope constraint ('most recent ... on the active sprite') front-loaded. Nothing is wasted.

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?

For a zero-argument tool with no annotations and no output schema, the description is adequate but not complete: it never says whether undo covers non-editing operations handled by siblings like create_frame or delete_layer, nor what the tool reports when the stack is empty. These are the details an agent needs to avoid surprising behavior.

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?

The schema has zero parameters and 100% description coverage, so the baseline is 4. The description correctly implies the tool is parameterless by describing an action applied to the current context rather than to a target argument.

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 uses a specific verb ('Undoes') and pins the resource and scope precisely: 'the most recent editing tool call or transaction on the active sprite.' That scoping distinguishes it from a broad history reset, though it never names the 'redo' sibling that an agent would naturally pair it with.

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 semantics of 'undo' -- there is no explicit statement of when to reach for this versus redo, nor any precondition (e.g. that an active sprite must exist). An agent can infer the intent, but nothing routes it between the two history tools.

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