create_session

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

With no annotations, the description must disclose behavior itself. It adds valuable context about isolation and independent MCP backend processes, but omits expected outcomes (e.g., return value, session handle), resource implications, and error conditions. This leaves significant gaps for an agent.

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?

Two short sentences, each conveying essential information: the action and the isolation/independence trait. No redundancy.

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?

For a simple one-parameter create tool, the description is adequate but incomplete. It fails to mention what the tool returns (a session identifier) or how the created session is referenced by sibling browser tools, which an agent needs to invoke subsequent operations correctly.

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 already provides 100% coverage with a clear description of the `backend` parameter including options. The description adds no additional parameter semantics, so the baseline score of 3 applies.

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 uses a specific verb ('Create') and resource ('new isolated browser session'), clearly distinguishing from sibling lifecycle tools like close_session and list_sessions. It also adds context about independent backend processes, reinforcing its unique role.

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 implies usage for establishing a new session before browser operations, but does not explicitly state when to choose this over alternatives or note prerequisites. Because sibling tools include session management tools, the context suggests lifecycle usage, but the description itself lacks explicit guidance.

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