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

Annotations already declare readOnlyHint=true, so safety is covered. The description adds meaningful behavioral context beyond annotations: targets are synthetic, shaped after published formats, and a job may provide its own target document, clarifying that this list is not exhaustive for all job contexts.

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?

Two sentences, both front-loaded and free of repetition. The first sentence defines the returned resource and its fields; the second adds a valuable scope caveat without excess.

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 zero parameters, a readOnly annotation, and an existing output schema, the description supplies enough conceptual context: what targets are, their synthetic nature, and the job-specific alternative. Minor gaps like ordering or pagination are reasonably left to the output schema.

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 parameter semantics are not applicable and the baseline is 4. The description does not need to explain any argument meaning, and the schema is empty.

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 identifies the resource as device targets the service knows by name and details what each contains (qubits, pairs, gates, T1/readout errors, hash). It does not explicitly contrast with the sibling show_target, which likely returns a single target, so sibling differentiation is left implicit.

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?

Usage is only implied: an agent can infer this is for discovering available named targets. The final sentence notes that a job may supply its own target document instead, which is useful context, but there is no explicit when-to-use guidance or named alternative like show_target.

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