browser_tab_new

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

With no annotation provided, the description carries full disclosure burden, but it only states the action and optional navigation. It fails to mention whether the new tab becomes active/focused, any return value (e.g., tab ID), or behavior with invalid session IDs. This lack of behavioral context is a significant gap for a state-changing 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?

The description is a single, front-loaded sentence with zero unnecessary words. It efficiently communicates the core function and optional navigation in a concise manner.

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 mutation tool with no annotations, no output schema, and a simple but under-described parameter set, the description leaves out critical context: what happens to the new tab (active vs background), how sessionId affects operation, and any return value. The sibling tool context does not rescue this as the description itself is incomplete.

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 coverage is 50%: sessionId has a description, but url does not. The description's 'optionally navigate it' merely duplicates the schema's implicit optionality (no required params) without adding format, meaning, or restrictions for the url parameter. It does not compensate for the missing schema description.

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 'Open a new tab and optionally navigate it' clearly states the tool's specific action and resource: creating a new browser tab with optional navigation. It distinguishes itself from sibling tools like browser_navigate, browser_tab_select, and browser_tab_close by focusing on tab creation.

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 usage for whenever a new tab is needed, but it does not explicitly contrast with alternatives like browser_navigate (for existing tabs) or browser_tab_select (for switching tabs). The 'optionally navigate' hint suggests URL handling, but no explicit when-to-use or when-not-to-use guidance is provided.

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