Step to the next or previous preset of an FX on a specified track by providing track index, FX index, and direction (1 for next, -1 for previous).
Step to next/previous preset.
Args: track_index: 0-based track index, or -1 for the master track. fx_index: 0-based FX chain index. direction: 1=next, -1=previous.
| Name | Required | Description | Default |
|---|---|---|---|
| fx_index | Yes | ||
| direction | Yes | ||
| track_index | Yes |
Changes observed during successful MCP inspections.
v0.3.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden of behavioral disclosure. It explains the direction parameter and index semantics, but does not mention side effects like whether the change is persistent, whether wrapping occurs at the first/last preset, or what happens if the FX has no presets. This is a significant gap for a state-mutating operation.
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?
One action sentence followed by a terse, well-formatted arg list. No filler or redundant content; every line earns its place and the core purpose is front-loaded.
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?
The description covers the action and all parameter meanings, which is enough to invoke the tool based on the simple schema. However, it does not describe the return value or edge-case behavior (e.g., no presets, wrap-around), and there is no output schema or annotations to fill that gap. This leaves some ambiguity about the outcome of the call.
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 does: each parameter gets meaningful semantics—track_index with the -1 master sentinel, fx_index as 0-based, and direction restricted to 1/-1. This fully documents the parameters beyond the bare type information.
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 ('step') and resource ('preset') on a specific track/fx context. The action of navigating next/previous is clearly distinct from sibling tools like fx_get_preset and fx_set_preset, which read or set a preset rather than step between them.
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?
No guidance on when to use this tool versus alternatives such as fx_set_preset or fx_get_preset. There are no conditions, exclusions, or hints about when stepping is the right choice, leaving the agent to infer usage from the name alone.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.