new_page

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

The readOnlyHint=false annotation already signals mutation, and the description adds that it returns a tab index. However, it does not disclose side effects such as whether the new tab becomes active, whether the URL is validated, or any failure modes. The description provides the essential behavior but is minimal.

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 two short sentences, front-loaded with the core action. No wasted words; every element contributes to understanding the tool's purpose and output.

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), the description adequately covers what it does and what it returns. It could mention whether the new tab is activated or if any restrictions apply, but for a basic 'new tab' operation this is nearly complete. The lack of an output schema is partially compensated by the explicit 'Returns tab index'.

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 the single 'url' parameter with 100% coverage. The description's 'at URL' phrase adds no further detail about URL formatting, required scheme, or behavior when omitted. Since schema coverage is high, the baseline of 3 applies.

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 function: 'Open new tab at URL. Returns tab index.' This is a specific verb+resource combination that distinguishes it from sibling tools like navigate_page (which likely navigates the current tab) and list_pages. The output is also specified.

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 implies when to use the tool (when you need to create a new tab at a given URL) but does not explicitly contrast it with alternatives like navigate_page or select_page. It lacks any exclusions or 'instead of' guidance, so usage context is only inferred.

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