audio_devices

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

Annotations already convey readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, so the description does not need to restate safety. It adds the 'available' qualifier, but does not mention what the returned list contains (e.g., names, IDs, default device) or whether it includes both sinks and sources in a single merged list or separate structures. This leaves some behavioral ambiguity beyond the annotations.

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 entire description is a single compact sentence that front-loads the action ('List') and the object ('available audio sinks and sources'). There is no filler, repetition, or extraneous information.

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 list tool, the description states enough to invoke the tool correctly. However, since there is no output schema, the lack of any detail about the returned structure (field names, whether it's a combined list, how to identify devices) is a small gap. The openWorldHint suggests the output may vary, but the description adds no guidance there.

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 input schema has zero propertieston, so there are no parameter semantics to clarify. The description's brevity is appropriate; no parameter information could add value here, and the baseline of 4 is justified.

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 ('List') and a precise resource ('available audio sinks and sources'), making it clear what the tool does. It naturally distinguishes itself from siblings like get_volume, set_output_device, and mute_audio by referring to the enumeration of sink/source endpoints rather than volume or device selection.

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 implies a use case (listing devices before selecting an output with set_output_device) but does not explicitly state when to use it versus alternatives, and it offers no exclusion criteria. For a simple list operation, the usage context is reasonably obvious, but the description itself provides no direct guidance.

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