umouse_set_audio_source

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

No annotations exist, so the description carries the full burden, and it discloses non-obvious side effects: other devices are muted at the SDK layer, the default policy is restored when device_id is omitted, and the call is refused by arbitration during an active voice session. It does not mention persistence, permissions, or what the response contains.

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?

Four short clauses with no filler, and the primary effect is front-loaded before the reset behavior and the rejection caveat. The parenthetical is slightly dense, but nothing is wasted.

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 one-parameter mutation tool with no annotations and no output schema, the description covers the effect, the reset semantics, and the failure condition. Missing details are relatively minor: permission requirements and whether the setting survives reconnection or session end.

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 coverage is 100%, and the schema already states that device_id is a device SN and that empty or omitted restores the default policy. The description repeats and slightly contextualizes this meaning but adds no syntax or format detail beyond the schema, so the baseline of 3 is appropriate.

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?

A specific verb (set) and resource (voice audio source device) with the effect spelled out: only that device is captured, other devices are muted at the SDK layer. This distinguishes it from umouse_audio_record and umouse_voice_start, which handle recording and session lifecycle rather than source 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?

It gives clear conditions: use when multiple devices are online and the recognition session needs to be locked to one source; omit device_id to restore the default first-come-first-served policy; it will be rejected while a voice session is in progress. It does not name a sibling alternative such as umouse_set_channel_pref, so it falls short of a 5.

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