browser_newTab

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

With no annotations provided, the description carries the burden of disclosure. It reveals the important behavioral detail that the new tab is automatically switched to, which is not inferable from the schema. It does not, however, mention any potential side effects (e.g., if the URL is invalid or if a blank tab is opened). For a low-complexity tool, this is good but not exhaustive, hence a 4.

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 sentences long, front-loaded with the core action, and every word adds value. It states the primary function, the optional behavior, and the automatic switching without any redundancy or filler.

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 its simplicity (1 optional parameter, no output schema, no annotations), the description provides complete information: what the tool does, the optional navigation, and the automatic switching. There are no hidden complexities requiring further explanation, making this a fully complete description.

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' parameter described as 'URL to navigate to in the new tab (optional)'. The tool description adds no further meaning beyond restating this in prose ('optionally navigate to a URL'). Since the schema already fully documents the parameter, a 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 identifies the action: 'Create a new browser tab' with an optional navigation step, and distinguishes itself from siblings like browser_goto (which navigates the current tab) and browser_switchTab (which switches to an existing tab) by explicitly mentioning the automatic switch. This is a specific verb+resource+scope statement.

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 a new tab is needed, optionally with a URL, and notes that it automatically becomes the active tab. It does not explicitly name alternatives or state exclusions, but the context is clear for a simple browser operation. A score of 4 is appropriate for clear context without explicit exclusions.

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