create_session

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It explains the two modes (existing vs. temporary profile), the CDP connection mechanism, and that all parameters are optional with sensible defaults. It does not mention potential side effects like persistence or cleanup, but for a creation tool this is acceptable.

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 with no filler. It front-loads the core purpose and then explains the key usage modes, making it highly efficient and easy to scan.

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 tool has 7 parameters and no output schema, but the description only explains the primary functionality. It does not mention return values (e.g., session ID) or how the created session relates to sibling tools like switch_session or close_session. This leaves a gap for an agent that needs to know what to expect after invocation.

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 the description adds marginal value beyond the schema. It clarifies that profileId is for connecting to an existing profile and that other parameters are for temporary profiles, which is echoed in the schema. The note about 'all parameters are optional' is helpful but already implied by zero required parameters.

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: 'Create a browser session by connecting to an NSTBrowser profile via CDP.' It specifies the resource (browser session) and method (CDP connection), and it is immediately distinguishable from sibling tools like list_sessions, switch_session, and close_session, which perform different operations.

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: 'Provide profileId to connect to an existing profile, or call with no arguments to create a temporary one.' This tells the agent when to use each invocation mode. It stops short of explicitly naming alternatives, but the sibling context makes the tool's distinct role clear.

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