new_page

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

Annotations already declare not read-only, not destructive, and not idempotent, but do not mention context switching. The description adds the important behavioral fact that after opening, the tool 'drives it from now on', indicating a persistent change in the agent's active target. This goes beyond annotations and provides valuable context.

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 a single, tightly worded sentence. The core action ('Open a new tab') is front-loaded, and the secondary clause ('drive it from now on') adds essential context without redundancy. No filler or unnecessary 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?

For a tool with only one optional parameter and an output schema, the description covers the primary behavior and the crucial context switch. It does not mention edge cases like opening a blank tab (implied by 'optionally at a URL') or how the previous tab is affected, but these are not critical for correct invocation. Overall, it provides sufficient information for an agent to use the tool effectively.

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 a single optional nullable url parameter, and description coverage is 0%—the description does not mention the parameter by name. However, it says 'optionally at a URL', which conveys the parameter's optionality, matching the schema. It adds minimal meaning (that a URL can be given) but does not explain format or behavior when omitted. Since coverage is low, the description should compensate more; this is adequate but not thorough.

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 opens a new tab and takes control of it. The verb 'open' and resource 'tab' are specific, and the phrase 'drive it from now on' distinguishes it from sibling tools like select_page or close_page, making the purpose unambiguous.

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 it (to create a new tab and make it the active context) but does not explicitly contrast with alternatives like goto (navigate current tab) or select_page (choose existing tab). There is no explicit 'use this when...' or 'instead of...' guidance, leaving some inference to the agent.

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