fx_get_instrument

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

With no annotations, the description carries the full burden. It discloses the return behavior, including the -1 sentinel for 'no instrument,' and documents that the operation is a lookup rather than a mutation. It could additionally state read-only semantics explicitly, but the get/find framing makes this reasonably clear.

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 short, front-loads the core function and return behavior, and then gives a compact parameter definition. Every sentence carries useful information without redundancy.

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 getter with no output schema, the description covers the essential invocation detail and return sentinel. The phrase 'params' is a bit vague, and it does not specify the return shape beyond that, but the tool is simple enough that this is a minor gap.

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?

Although schema coverage is 0%, the description fully explains the only parameter: track_index is 0-based and -1 targets the master track. This goes well beyond the bare integer type in the input schema.

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 states a specific verb and resource: 'Find VSTi instrument on track' and tells what it returns ('index + params, or -1 if none'). This differentiates it from the many FX and track listing tools, though it does not explicitly distinguish it from sibling get_track_instruments.

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 provides clear context: use this when you need the VSTi instrument on a given track, including master-track handling. However, it gives no explicit guidance on when to prefer a sibling such as get_track_instruments or fx_get_params.

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