spotify_devices

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds the qualifier 'available,' implying it returns only currently active devices, but this is more purpose than behavior. No additional insights like auth requirements or rate limits are provided, so a 3 is appropriate given the strong annotation coverage.

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, front-loaded with the action, and no filler. The examples in parentheses add useful clarification without bloat, and the usage sentence earns its place.

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?

For a zero-parameter, read-only tool with comprehensive annotations, the description is sufficiently complete. It covers what and when, and the safety profile is handled by annotations. It doesn't mention possible Spotify auth prerequisites, but that is a minor omission for a simple listing operation.

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 confirms this with 100% coverage. Per scoring rules, the baseline for 0 params is 4. The description doesn't need to clarify parameter meanings since there are none.

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 states a clear verb ('Get list') and resource ('Spotify playback devices') with examples, making the tool's purpose unambiguous. It doesn't explicitly name sibling tools like audio_devices to differentiate, but the 'Spotify' qualifier inherently distinguishes it.

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 provides an explicit usage trigger: 'Use when the user asks what devices are available for playback.' This gives clear context, though it does not mention alternatives or exclusions, which prevents a 5.

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