Show a screen on the user's display

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

With no annotations, the description carries the full transparency burden. It discloses a key behavioral trait: 'The browser normally sits parked offscreen, so nothing is visible until this is called.' This adds valuable context beyond the schema, explaining why the tool is necessary and what you can expect if you don't call it.

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 concise sentences front-load the main purpose and immediately follow with usage guidance. No redundant wording or filler – every sentence contributes essential information.

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 straightforward UI-control tool with no output schema, the description covers the essential context: what it does, when to use it, and why it's needed (offscreen browser). It doesn't describe edge cases like what happens if the project ID is invalid, but such details aren't critical for this kind of atomic action.

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 already documents most parameters (path, chatId, visible) with descriptions, covering 75%. The description references these parameters indirectly ('open a project', 'specific chat', 'specific file') but doesn't add new syntax or format details, so it adds minimal value beyond the schema.

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 the tool's purpose: bringing the Claude Design window on screen and opening a project, chat, and file for the user to watch. It uses specific verbs (bring, open) and references the resource, distinguishing it from siblings like close_browser or send_prompt.

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 provides explicit usage context: 'Use this before send_prompt when the user should see the work happen, and to show them a finished screen.' It also explains the crucial background behavior that the browser is normally offscreen, making the need for this tool clear. It stops short of listing when not to use it or naming alternatives explicitly, so it doesn't earn a 5.

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