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

Annotations already establish read-only, idempotent, non-destructive, closed-world behavior. The description adds valuable context that this operates on a verified connection, distinguishes guest versus personal account state, and explicitly warns against using it for linking, switching, account creation, or trusting an email hint.

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?

The description is two sentences and front-loads the core purpose before listing exclusions. Every clause earns its place by clarifying account-type detection and preventing misuse.

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 tool has no parameters, rich annotations, and an output schema, so the description does not need to explain return values. It is complete for a low-complexity identity check: it says what it determines, when to call it, and what it must not be used for.

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?

There are zero parameters, so there are no parameter semantics to explain. The baseline for a zero-parameter tool is 4, and the description does not need to compensate for any schema description gap.

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-resource pair: identify whether the verified connection is a guest session or a personal TriFit account. It explicitly distinguishes this read-only identity check from account creation, linking, switching, or trusting an email hint, which separates it from siblings like get_trifit_profile and create_trifit_try_on.

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 clearly states the timing: use this before choosing tools. It also gives strong exclusions: does not link, switch, create an account, or trust a conversational email hint. The only gap is that it does not name sibling tools as alternatives, such as get_guest_demo_status for guest demo state.

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