rivian_login

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

Annotations only declare the generic profile (readOnlyHint=false, openWorldHint=true, destructiveHint=false); they do not describe the interactive, multi-step nature of this flow. The description adds real value by disclosing that a second OTP call may be needed, but it doesn't say what credentials are used, whether a browser is opened, or what state is established on success.

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, front-loaded with the action and followed immediately by the conditional follow-up. No filler, nothing redundant.

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 zero parameters and no output schema, the description covers the essential flow, but for an auth entry point it leaves real questions open: where the credentials come from, whether the call blocks waiting for the OTP, and what a successful login enables for the sibling read tools.

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 tool takes zero parameters, so the schema carries no parameter semantics for the description to supplement. Baseline 4 applies; there is nothing in the description that misleads about inputs.

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?

"Sign in to Rivian" is a specific verb+resource that an agent can immediately distinguish from the read-only sibling tools like rivian_get_vehicle_state. It doesn't explicitly say it is the entry point of the auth flow for the other tools, but the purpose is 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?

It routes the agent correctly by naming rivian_submit_otp and the exact condition that selects it (Rivian sends a verification code). It doesn't state prerequisites such as required credentials or session prerequisites, but it gives clear usage context with no real alternative to confuse the agent.

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