browser_open

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

No annotations are provided, so the description carries the burden. It mentions that the session is 'stateful' and returns a session_id, but does not disclose details like whether it launches a real or headless browser, session limits, or resource implications. Additional behavioral context would improve transparency.

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 two short sentences. The first sentence states the primary purpose. The second sentence provides usage patterns and context. There is no extraneous information, and the most important 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 no parameters and an output schema exists (as indicated by context signals), the description adequately covers the tool's purpose, return value (session_id), and usage context. It is complete for an init tool that requires no additional configuration.

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, and schema coverage is 100% by default. The description does not need to add parameter semantics, as there are none. Baseline for no parameters is 4.

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 tool opens a new stateful browser session and returns a session_id. It distinguishes itself from sibling tools like browser_navigate and browser_click, which require an existing session. The verb 'Open' and resource 'browser session' are specific.

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 provides explicit guidance on when to use this tool: before using browser_navigate, browser_click, etc., and for auditing pages behind logins or multi-step journeys. It lists the sequence of tools that follow. However, it does not explicitly state when not to use it or what to do if a session already exists.

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