List live sessions

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

The description accurately reflects the read-only nature (no side effects) consistent with the readOnlyHint annotation. It adds useful detail about what information is returned (URL, observation number, idle time), which goes beyond the bare annotation, though it does not explicitly state that no sessions are modified or destroyed.

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, compact sentence that conveys all necessary information without redundancy or extraneous details. It is well-structured and immediately clear.

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 the lack of an output schema, the description provides sufficient context by naming the specific fields (current URL, observation number, idle time) that will be included in the list. This is adequate for a simple listing operation, though it could mention that the list is non-empty or how sessions are ordered, but these are minor gaps.

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?

The tool has no parameters, so the input schema is fully transparent (100% coverage). The baseline for zero parameters is 4; the description does not need to add anything about parameters, and it does not introduce any ambiguity.

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 action (list live sessions) and specifies the included details (current URL, observation number, idle time). It is distinct from sibling tools like browser_session_open and browser_session_close, which handle session lifecycle, not listing.

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 does not explicitly state when to use this tool versus alternatives. While the distinction from open/close is obvious from the tool name, the description lacks explicit guidance such as 'use this to check active sessions before opening a new one' or comparisons to other browser_session_* tools.

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