new_page

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

No annotations are provided, so the description carries the full burden. It states the tool opens a new tab and returns the tab index, but lacks details on whether the new tab gains focus, how it handles invalid URLs, any loading behavior, or potential errors. The description is very minimal for a tool that changes browser state.

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: one sentence of 10 words that conveys the tool's purpose and output. No unnecessary information. This is ideal for quick parsing by an AI agent.

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?

Given the tool's simplicity (one parameter, no output schema, no annotations), the description is minimally adequate. However, it lacks any behavioral details that would help an agent use it correctly, such as error handling or side effects. For a very simple tool, a 3 is reasonable.

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?

There is only one parameter (url) with 100% schema coverage and a clear description ('Target URL'). The tool description adds the context that the URL is for a new tab, but doesn't add additional semantics beyond what the schema provides. Baseline score of 3 is appropriate.

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 action ('open'), resource ('new tab'), and the required input ('URL'). It also mentions the output ('Returns tab index'). This distinguishes it from sibling tools like navigate_page (which navigates an existing tab) and list_pages (which lists tabs).

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 does not provide any guidance on when to use this tool versus alternatives. For example, it doesn't mention that opening a new tab is preferred over navigating an existing tab when the user wants to preserve the current page, or that select_page should be used to focus a tab after opening. No exclusions or context are given.

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