open_tab

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

No annotations are provided, so the description carries the full behavioral burden. It usefully discloses that this drives the user's real Chrome browser via an extension and that the tab becomes the task's active tab going forward — significant side effects — but says nothing about permissions, tab limits, or failure behavior when the extension is unavailable.

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?

A single sentence with the environment caveat bracketed up front and the action plus its persistent effect packed in afterward. No filler 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 two-parameter navigation tool with no output schema and no nested objects, the description covers what the agent needs: it acts on a real browser, opens a tab, and makes that tab the task's working tab. The missing piece is differentiation from the many navigation siblings.

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 100% with only two parameters ('url' and 'intent'), so the schema already documents both. The description adds no syntax, format, or URL requirements beyond what the schema states; the baseline of 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 URL in a new tab') and adds a meaningful side effect: the new tab becomes this task's tab. It does not explicitly distinguish itself from the adjacent sibling go_to_url, which an agent must infer covers in-place navigation rather than a new tab.

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?

Provides clear gating context — 'use only when the task requires acting on a real website' — which tells the agent when not to use it. However it never names the alternative (go_to_url, switch_tab, run_recipe) or contrast conditions, so the routing decision remains partly inferred.

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