new_session

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It clearly states the destructive side effect of clearing all existing sessions, which is essential information. It does not elaborate on additional effects (e.g., cookies, cache, or whether it terminates running jobs), but for a zero-parameter tool this is sufficient context.

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, direct sentence that front-loads the action ('Start a fresh browser session') and immediately discloses the key side effect. There is no repetition or filler, making it highly concise and well-structured.

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 tool with zero parameters, an output schema, and no annotations, the description fully explains the tool's purpose and its primary side effect. It is complete enough for an agent to decide when to invoke this tool and what to expect, especially given the clear sibling context.

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 zero parameters, so there is no schema coverage concern. The baseline for 0-parameter tools is 4, and since the description adds no false or missing parameter details, this score is appropriate.

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 ('Start') and resource ('browser session'), and clearly distinguishes the tool from siblings like clear_session or list_sessions by stating it starts a fresh session while clearing all existing ones. This makes the tool's purpose unambiguous and unique.

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 the tool should be used when a brand-new session is needed, and the phrase 'clearing all existing sessions' serves as an implicit exclusion (i.e., if you want to keep existing sessions, this is not the tool). However, it does not explicitly name alternatives or provide when-not-to-use guidance, so it falls short of a 5.

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