quantum_backends

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint, so the safety profile is covered. The description adds that the result includes availability, queue lengths, qubits, and gates, which is useful context, but it does not disclose pagination, refresh behavior, or rate-limit constraints.

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 listing the resource and its key attributes. There is no filler or repetition, and the important scoping phrase ('for an instance') is placed at the end without obscuring the main action.

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?

An output schema exists and rich annotations cover the safety profile, so those do not need repeating. However, with two optional parameters at 0% schema description coverage, the description does not fully equip an agent to use the min_num_qubits filter or understand the instance parameter.

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?

Schema description coverage is 0%, so the description must explain both parameters. It mentions 'instance' but does not clarify whether it is optional, what a valid instance identifier looks like, or that min_num_qubits filters the returned backends. The parameter meaning is therefore largely left to inference.

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 ('List') and resource ('accessible QPUs'), and enumerates the returned attributes. It does not explicitly differentiate itself from sibling tools such as quantum_instances, but the purpose is clear.

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 'for an instance' implies scoping but gives no explicit guidance about when to use this tool versus quantum_instances, quantum_configuration, or other siblings. There are no exclusions or alternative-routing instructions.

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