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

Annotations already mark the tool as readOnly, openWorld, idempotent, and non-destructive. The description adds valuable behavioral context: the Business tier requirement, current sign-in status, the server's auth-challenge response, and a directive to avoid fabrication. This goes beyond annotations and does not contradict them.

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 front-loaded with the core purpose and then provides focused, necessary guidance on auth handling and no-fabrication policy. It is somewhat verbose for a zero-parameter tool, but each sentence earns its place and there is no fluff.

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 no parameters and no output schema, the description covers the key aspects: what the tool does, the Business tier requirement, how to handle signed-out users, and the expected auth challenge. It doesn't describe return fields or list structure, but for selection and invocation it is sufficiently complete.

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 has zero parameters, and the schema coverage is trivially 100%. There are no parameter semantics to explain, and the baseline for a zero-parameter tool is 4. The description appropriately says nothing about parameters.

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 clearly states the tool returns Bluetooth devices seen at the user's business locations, using 'YOUR business locations' to convey scope and distinguish it from general location tools. It lacks an explicit verb like 'list' or 'get', but the noun phrase is serviceable. It doesn't explicitly name sibling alternatives, so it stops short of a 5.

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 explicitly addresses when to call the tool despite the Business tier requirement, instructing the agent to call for the user's own business, reseller, or licensed data and explaining the expected auth challenge. It also warns against fabricating answers. However, it doesn't explicitly state when not to use it or name alternative tools, so it falls short of explicit when-not/alternatives guidance.

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