browser_new_tab

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

With no annotations, the description carries the full behavioral burden and largely fails. It doesn't say whether the new tab becomes the active/selected tab, whether cookies/session state is shared with existing tabs, or whether the call returns a tab handle — all of which matter for a tab-creation tool.

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?

One clean, front-loaded sentence with no filler or redundancy. It is efficient, though its brevity is partly why other dimensions are thin.

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 tab-creation operation amid dozens of browser siblings and with no annotations or output schema, the description omits what an agent most needs: relationship to browser_navigate/browser_new_isolated_tab and post-call tab state. It is under-specified rather than complete.

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?

Schema description coverage is 100%, with the url property documented and defaulted to about:blank in the schema itself. The description only restates 'specified URL', adding no format, scheme, or behavior detail beyond the schema, so baseline 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?

States a specific verb and resource ('Open a new browser tab') plus the key input (URL), so an agent knows what the tool does. It does not distinguish itself from close siblings like browser_new_isolated_tab or browser_navigate, which is the main reason it falls short of a 5.

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?

There is no guidance on when to use this versus browser_navigate (which also takes a URL) or browser_new_isolated_tab (which also creates a tab), nor any mention of prerequisites or resulting tab focus. Usage must be inferred entirely from the name.

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