Records the Mac microphone for a set duration to capture audio a connected iPhone or iPad plays, then returns the WAV file path.
Record the Mac microphone for a number of seconds (e.g. to capture what the device plays). Returns the WAV path.
| Name | Required | Description | Default |
|---|---|---|---|
| seconds | Yes | ||
| audioDevice | No | Mac input name substring (default: built-in mic, never an iPhone/iPad mic) |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations present, the description carries the full burden: it discloses only that it records the built-in Mac mic and returns a WAV path. It omits whether the call blocks for the full duration, whether macOS microphone permission prompts can occur, where the file is written, and whether prior recordings are overwritten — all material for a capture tool.
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 short sentences, zero filler, with the action and scope front-loaded and the return value stated second. 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 simple two-parameter capture tool with no output schema, the description covers what it does and what it returns, which is close to sufficient. It could mention the 300-second cap and permission/blocking behavior to be fully self-contained.
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 50%: audioDevice is already documented in the schema, while 'seconds' has no schema description. The description compensates partially by framing 'seconds' as a recording duration and by tying the tool to 'the Mac microphone' (reinforcing the audioDevice default), but gives no format or range guidance.
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 and resource ('Record the Mac microphone') plus the duration semantics and the return value ('Returns the WAV path'). No sibling tool (tap, screenshot, list_devices, etc.) overlaps with audio capture, so an agent can identify it immediately.
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 parenthetical '(e.g. to capture what the device plays)' gives a concrete use context that clarifies why an agent would choose this over screenshot/describe_ui. It names no alternatives or exclusions, so it stops short of full routing guidance, but the intent is clear.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.