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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds genuinely new context: the status is scoped to "this connection" (per-session, not account-wide), and it is a precondition for three named operations, which tells the agent to gate those calls on this check.

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: what it reports, why it matters, and the decision it should precede. The dependency list and the action directive are front-loaded with no filler or repetition.

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 must imply the return value, and "report whether the client is signed in" reasonably signals a boolean status. It does not clarify whether identity or account details come back with a positive result, which leaves a small ambiguity for a tool whose annotations and empty schema otherwise make it simple.

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 schema takes zero parameters, so there is nothing for the description to disambiguate; the baseline of 4 applies. The description correctly does not waste space restating the empty input.

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?

"Report whether the client is signed in to Norm on this connection" gives a specific verb (report) and a specific state to read, which is clearly distinct from the mutation siblings like sign_out and book_appointment. It stops short of naming any sibling to contrast with, so an agent must infer the sign_in/sign_out boundary from the name alone.

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 states a concrete trigger: call it before telling the client they need to sign in, and it notes that booking, listing and cancelling all depend on the signed-in state. It gives no explicit "when not to use" or cheapest-first framing, but the guidance is specific enough to route an agent correctly.

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