Assign a hardware input or virtual MIDI source to a track for recording, or use -1 to disable input.
Set the record input for a track.
Args: input_index: Input index (-1=no input, 0+=hardware inputs, 4096+=virtual MIDI).
| Name | Required | Description | Default |
|---|---|---|---|
| input_index | Yes | ||
| track_index | Yes |
Changes observed during successful MCP inspections.
v1.7.3Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations only provide destructiveHint: false, so the description carries some burden for behavioral disclosure. It adds context by explaining input_index ranges (-1, 0+, 4096+), which is useful. However, it does not describe the effect of setting the input, potential side effects, or requirements. This is more than annotation-only, but still limited.
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 description is extremely concise, with a clear subject line and a well-formatted args section. The most important semantic detail (input_index meaning) is front-loaded. There is no wasted text.
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?
With two parameters and no output schema, the description explains one parameter but leaves the other (track_index) unexplained. It also does not mention the broader context of recording or what 'record input' implies. This is not complete for an agent to confidently use the tool without additional knowledge.
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 description coverage is 0%, so the description must compensate. It explains input_index semantics clearly (no input, hardware, virtual MIDI), but provides no explanation for track_index. This partial compensation is inadequate for a 0% coverage schema, but the explanation provided is meaningful.
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 states the action: 'Set the record input for a track.' This is a specific verb-resource pair. It does not explicitly differentiate from sibling tools, but the purpose is unambiguous. It does not restate the name or title.
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?
There is no guidance on when to use this tool versus alternatives. It does not mention any conditions, prerequisites, or exclusions. The description simply states what it does, leaving the agent to infer usage context from the tool name alone.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.