tab_new

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

Annotations already declare openWorldHint=true and destructiveHint=false, so the safety profile is covered. The description adds a useful side effect beyond annotations: the new tab becomes current. It does not describe whether the tab is foregrounded, what happens on invalid URLs, or how the output schema reports the tab.

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 front-loaded sentence with the core action first and the optional modifier second. No wasted text.

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 simple one-parameter browser tool with annotations and an output schema, the description is nearly complete. The main missing piece is how it relates to navigate and whether the previous tab remains open, but that is minor given the low complexity.

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?

With one optional parameter and 0% schema description coverage, the description carries the burden and does so reasonably: it says the URL is optional and implies an empty value opens a blank tab. It does not specify URL format or relative-vs-absolute handling.

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 tab) and adds the scope detail that it becomes the current tab. It is distinguishable from navigate and tab_select by the word 'new', though it does not explicitly name those siblings.

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?

Usage is implied by the name and the optional URL behavior, but there is no explicit guidance on when to use this versus navigate (open in a new tab vs reuse current) or tab_select. The agent must infer the distinction.

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