Check the sign-in

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

Annotations already establish the safe read-only/idempotent profile, and the description adds substantial context beyond them: the fallback to a cached account when no browser sign-in occurred, the guarantee that no token is ever returned, and the fact that the call returns immediately (non-blocking). These are behavioral traits an agent could not infer from the structured fields.

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?

Every sentence earns its place: the return-state enumeration, the cached-account edge case, the no-token guarantee, and the polling instruction. The purpose is front-loaded and there is no filler.

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?

There is no output schema, but the description enumerates all return states and their meanings, so an agent knows exactly what to expect. Combined with the fallback and no-token notes, nothing needed to call or interpret this tool is missing.

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 per the rubric the baseline is 4; there are no parameter semantics for the description to clarify. The description does not need to compensate for anything here.

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 states a concrete verb and resource (reports the state of the browser sign-in started by auth_begin_login) and enumerates the exact values it can return. It clearly distinguishes itself from its sibling auth_begin_login, which starts the flow rather than reporting on it.

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 gives explicit usage direction ('Poll it rather than waiting') and ties itself to the prerequisite auth_begin_login, which is clear context for when to call it. It stops short of naming alternatives or stating when not to use it, e.g. versus the sibling session_status, so it falls just short of a 5.

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