New session

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

No annotations are provided, so the description carries the full burden. It mentions 'isolated browser session' and 'returns a session id', but does not disclose behavioral traits such as whether the session is headless, destructive effects (e.g., closing existing sessions), authentication needs, rate limits, or whether it opens a visible browser window. The notes on engine options (e.g., 'real Chrome', 'single-session') add some context but are insufficient for a complete behavioral picture.

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 extremely concise: two sentences with no filler. The first sentence states the core purpose, the second lists engine options with brief annotations. Every word adds value, and the most critical information is front-loaded.

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 tool has only one parameter, no output schema, and no annotations, the description provides the essential purpose and parameter details. However, it lacks details on the return format (just 'session id' without type or structure), implications of 'isolated', and any error conditions. It is adequate but leaves some 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 schema has one parameter 'engine' with enum values but 0% schema description coverage. The description adds significant meaning by explaining each engine option: 'chrome (real Chrome)', 'chromium', 'webkit (Safari engine, multi)', 'safari (real Safari.app, single-session)'. This goes beyond the raw enum values and helps the agent choose appropriately.

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 'Open an isolated browser session' with the verb 'open' and resource 'isolated browser session'. It also lists engine options and mentions 'Returns a session id', which distinguishes it from sibling tools like browser_attach (attaches to existing session) and browser_list_sessions (lists sessions).

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. It lists engine options but provides no guidance on which to choose or scenarios where this tool is appropriate. There is no mention of prerequisites, required context, or when not to use it.

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