open_tab

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

With no annotations provided, the description discloses key behaviors: the tab is persistent, returns a tab_id, and remains open until explicitly closed or the session expires. It does not cover failure modes or resource implications, but the core lifecycle behavior is clearly stated.

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?

Two compact sentences with the primary action first, followed by return value and lifecycle semantics. Every sentence earns its place with no filler or redundancy.

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?

The description covers everything needed to invoke the tool correctly: it explains what it does, what it returns, and how long the tab persists. Since there is no output schema, the explicit mention of tab_id is essential and sufficient. The schema handles parameter details, so nothing critical is missing.

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%, so the schema fully documents both parameters. The description adds no extra semantic detail about them, but it doesn't need to; it focuses on the tool's overall behavior.

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 uses a specific verb and resource ('Open a new persistent browser tab') and distinguishes itself from siblings like fetch_page by emphasizing persistence and returning a tab_id for multi-step workflows. This makes the tool's role clear and easily differentiated.

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 explicitly identifies the intended use case: multi-step workflows such as login, navigation, and form filling. It doesn't name alternative tools or state when not to use it, but the persistent-tab framing and tab_id return value imply the contrast with single-shot tools like fetch_page.

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