browser.fork_session

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

Annotations include openWorldHint=true and destructiveHint=false, indicating it creates a new state without destroying existing ones. The description adds that it snapshots cookies/storage/URL and creates an 'independent' session, clarifying that the original is unaffected. This is useful context, but it doesn't mention error scenarios or edge cases (e.g., if session_id is invalid), so it doesn't go beyond the annotations' baseline significantly.

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 sentences, front-loading the core action and how it works, then adding the use case. Every sentence adds value; no fluff or redundancy. Ideal length for a tool of this complexity.

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 output schema and moderate complexity (3 params, all optional), the description covers the core function and expected use. It could mention potential errors or post-conditions (e.g., new session's status), but the description is adequate for an agent to decide to use it and understand the result. The high schema coverage compensates for missing param details.

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 provides 100% description coverage for all three parameters (name, start_url, session_id), each with clear defaults. However, the description adds no additional parameter-level detail, but since the schema is thorough, a baseline of 3 would be standard; the description's overall context about forking helps interpret the parameters, justifying a 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 action ('Fork a session'), the resource ('session'), and the mechanism ('snapshot its cookies, storage state, and current URL, then create a new independent session'). It also distinguishes from siblings by specifying it is for branching workflows, which aligns with the purpose of create/edit/delete operations, unlike list/get/observe 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 provides clear context for when to use the tool ('branching workflows or running parallel variants') and implies it builds on create_session/list_sessions. It doesn't explicitly exclude alternatives like create_session, but the use case is well-defined. The 'openWorldHint' annotation suggests side effects are expected, which the description aligns with.

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