browser_new_session

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

No annotations are provided, so the description carries full responsibility. It discloses key behaviors: it creates a 'stealth' session, runs proxyless by default, supports proxy settings, persistence, headless mode, HAR recording with filtering, and storage state. It does not mention rate limits or auth, but for a creation tool, this is sufficient.

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 relatively long but well-structured, starting with the main purpose and then listing parameter details. Each sentence adds value, though it could be slightly more concise. The use of bullet-like format aids readability.

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's complexity (11 parameters) and the absence of output schema, the description provides adequate context. It mentions the return value (id), explains default session behavior, and covers key parameters. However, it could mention more about the session lifecycle or error cases.

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 add meaning. It explains most parameters: persistent, headless, record_har, har_url_filter, storage_state, proxy_url, proxy_server (with username/password), no_proxy. It provides example values for har_url_filter. However, it does not mention the 'label' parameter, leaving it undocumented.

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 verb 'Create' and the resource 'stealth browser session', and specifies that it makes the session current and returns its id. It also distinguishes itself by noting that most tools auto-create a default session, so calling this is optional, which helps differentiate it from other browser tools.

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 explicitly says 'Most tools auto-create a default session, so calling this is optional,' which provides when-to-use guidance. It also explains proxy configuration details and mentions an alternative for screen recording. However, it does not directly compare to sibling tools like browser_close_session or browser_list_sessions.

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