Confirm a visibly loaded exact preview

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the agent knows it is a safe read-only operation. The description adds the behavioral context that it is an app-only confirmation occurring after specific user actions, which goes beyond the annotations. It does not contradict the annotations, and it provides additional context about the tool's operation within the workbench flow.

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?

The description is extremely concise, consisting of two short sentences. The first sentence establishes the tool's scope ('App-only confirmation'), and the second adds the precise invocation conditions. Every word earns its place, with no unnecessary filler or duplication of schema details.

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?

The description provides adequate context for when the tool is called, but it fails to explain the meaning of the only parameter, which is critical for proper invocation. Since there is no output schema, the user cannot infer the return value. For a simple confirmation tool with a single opaque token, the description is minimally adequate but leaves the agent guessing about the parameter's role.

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 single parameter 'previewChallenge' has zero schema description coverage, and the tool description provides no explanation of its meaning, format, or purpose. The parameter appears to be an opaque challenge token, but the agent is left with no guidance on what to pass. This is a critical gap for a required string parameter, and the description does nothing to compensate.

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 clearly states it is an app-only confirmation step, which distinguishes it from the headless variant. It specifies the conditions (after exact image load event and explicit user click) that define its purpose. However, it does not explicitly identify the resource being confirmed (e.g., 'the selected preview'), so it's slightly less precise than the calibration example.

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?

The description explicitly states when to call this tool: 'only after the exact image load event and an explicit user click.' It also states 'App-only' which implicitly distinguishes it from the headless sibling (figure_library_confirm_selection_headless). This provides strong usage guidance, including a precondition for invocation.

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