Open and switch between multiple named browser tabs

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

With no annotations provided, the description carries the behavioral transparency burden. It discloses important invariants: open makes the tab active, close never closes the last tab, the default tab is 'main', and other tools act on the active tab. It does not specify edge-case behavior such as closing the currently active tab, but the essentials are covered.

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 dense but well-organized: it front-loads the use case, enumerates the actions in a compact list, and then adds the global active-tab rule and default label. Every clause carries operational meaning, with no 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?

Given no output schema and no annotations, the description does a good job: it explains what list returns and covers active-tab semantics, default label, and the never-close-last constraint. It does not state what open/switch/close return on success, but their effects are inferable from the stated behavior.

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 baseline of 3 applies. The description mostly restates what the schema already says about the action parameter and label, adding no genuinely new parameter-level meaning beyond the schema's own descriptions.

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 states the tool's function: keeping multiple labeled browser tabs open and switching between them. It enumerates the four operations (open, switch, close, list) and explicitly distinguishes the tool from siblings with 'Every OTHER tool acts on the ACTIVE 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?

The description gives a strong usage context: use this when you need multiple concurrent real tabs with preserved state, and it clarifies that other tools operate on the active tab. It does not explicitly name alternatives or state when not to use the tool, but the guidance is clear enough for an agent to choose correctly.

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