browser_open

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

Annotations declare readOnlyHint=false and openWorldHint=true, so the agent already knows this creates state and reaches the network. The description adds genuinely new traits: the session is stealth and persistent, it is referenced by a returned session_id, cookies can be seeded from web_login via profile, and it must be released with browser_close. It stops short of disclosing resource cost or concurrent-session limits.

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?

Four short sentences, front-loaded with the action and return value, then when-to-use, then the alternative, then lifecycle. No sentence is wasted.

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?

Covers opening, the session_id contract, cookie/profile reuse, the alternative tool, and the required teardown via browser_close. With no output schema needed beyond the stated session_id and full parameter coverage, nothing an agent needs to invoke this correctly is missing.

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 100%, so all three parameters are already documented, including proxy, profile, and visible defaults. The description reinforces profile's link to web_login but adds no syntax or format detail beyond the schema, so the baseline 3 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?

States a specific verb+resource ('Open a persistent stealth browser session') and names the return value ('session_id for browser_do'), which lets an agent distinguish it from web_act, browser_setup, and browser_do without opening a schema.

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?

Gives explicit when-to-use ('multi-step work where cookies and page state must survive between calls') with concrete examples (login then browse, cart then checkout), names the alternative for the simple case ('For one page and a few actions web_act is simpler'), and states both the profile-reuse path and the closing tool.

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