sign_in

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

With no annotations, the description carries the full behavioral burden. It discloses that a real browser opens, the agent never sees the password, and a mandatory completion step is required. These are critical behavioral traits an agent would not otherwise know.

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?

Three short sentences, each earning its place. The main action is front-loaded, followed by necessary caveats about password privacy and the mandatory complete_sign_in step. No filler or 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?

The description covers the essential behavior, security boundary, session naming, and mandatory follow-up. It doesn't mention error cases or what the output represents, but an output schema exists, so return-value details are not the description's responsibility.

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 0%, so the description must compensate. It thoroughly explains `name` as a durable session id with an example, but `url` is only indirectly implied by 'log into a website.' The description partially compensates but not fully for both 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 uses a specific verb and resource: it opens a real browser for the user to log into a website. It clearly distinguishes this tool from sibling tools like browse and complete_sign_in by framing login as a user-driven interactive step.

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 gives strong sequencing guidance: after login, the agent MUST call complete_sign_in before browsing. It also explains that `name` is a durable session id. It doesn't explicitly state when sign_in is preferred over browse, but the login-flow context makes this reasonably clear.

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