browser_use

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

With no annotations, the description carries the behavioral disclosure burden. It does disclose a meaningful state-changing behavior: it sets a session that other tools target by default. However, it does not mention what happens if the sessionId is invalid, whether the previous session is lost, or any side effects.

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 no wasted words. It states the action and the consequence clearly and efficiently.

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 setter, the description covers the core behavior and the target state. It does not mention prerequisites like starting or listing sessions, but given the low complexity and the parameter name, an agent has enough information to invoke the tool correctly.

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 0%, so the description must compensate for the undocumented parameter. The description only tells the agent that a session is being set; it does not explain how to obtain a sessionId or what format it should take. The parameter name 'sessionId' is self-explanatory, but the description adds little semantic value beyond it.

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 ('Set') and resource ('active session'), and clarifies the effect: other tools target this session by default. It does not explicitly distinguish itself from sibling tools like browser_use_tab or browser_sessions, but the focus on session-level state is reasonably clear.

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 this should be called before using other browser tools, but it gives no explicit guidance on when to use this versus alternatives such as browser_use_tab or session_restore. There are no exclusions or alternative recommendations.

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