Check sign-in status

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

Annotations already declare readOnly/idempotent/non-destructive, so the bar is low; the description still adds real value by disclosing that a failure state includes 'the fix' (remediation guidance in the response) and by explicitly stating 'Never returns a token,' which is a meaningful security assurance for an auth tool.

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?

A single front-loaded sentence that lists the possible states first and closes with the key caveat. Every clause earns its place with 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?

With no output schema, the description carries the return-value burden and largely does so by naming the three terminal states and noting that failures include remediation. It is nearly complete, though it doesn't indicate whether the status is transient (i.e., whether the agent should poll repeatedly) or describe any rate/retry behavior.

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. The description correctly adds nothing about inputs because there are none, and the empty schema is consistent with that.

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?

States a specific verb ('Reports') and resource ('background browser sign-in') and enumerates the three possible outcomes (pending, signed in, failed). It implicitly separates itself from auth_begin_login, but it never names or contrasts with the nearby session_status sibling, so an agent must still infer which status tool to call.

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 phrase 'where the background browser sign-in has got to' implies this is a polling/status-check tool to be used after starting sign-in, but it never explicitly says when to use it, when not to, or that auth_begin_login is the initiating counterpart. Usage is only implied.

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