Create session

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

No annotations provided, so the description must cover behavioral traits. It discloses isolation and concurrency, but lacks details on authentication requirements, error handling (e.g., duplicate sessionId), rate limits, or session lifecycle. This is adequate but not comprehensive.

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 sentences efficiently convey the core function and key behavioral trait. Front-loaded with the primary action, no filler, and every word adds value.

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?

The description covers purpose and isolation behavior, but with no output schema, it omits return value information (e.g., session details). It also does not connect to sibling tools or sequence (e.g., use before browser_navigate). Adequate for a simple tool, but missing context for full agentic use.

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%, and the schema's descriptions already explain each parameter. The tool description adds no extra semantic value beyond the schema; it only reiterates isolation context. Baseline 3 is appropriate given high coverage.

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 it creates an isolated browser session, distinguishing it from operations within a session. It explicitly mentions separation of cookies, storage, and tabs, and that multiple agents can drive separate sessions, making the purpose specific and unambiguous.

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 implicitly indicates when to use this tool (when isolation is needed), but does not explicitly state prerequisites (e.g., must create a session before other browser actions) or exclude scenarios. A clear usage context is provided, but alternative or when-not-to-use guidance is absent.

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