save_fx_preset

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

Annotations declare destructiveHint=true, but the description says the tool always returns an error and therefore cannot perform a destructive update. That directly contradicts the annotation's destructive warning; per rubric this is an annotation contradiction.

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, with the unsupported status and the alternative front-loaded. No sentence is redundant.

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 an unsupported stub, the description gives the essential behavior (always errors) and a concrete next step. It leaves parameter meanings unexplained, but those are largely irrelevant because the call cannot succeed.

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?

All three parameters have 0% schema description coverage, and the description only hints at preset_name via 'named FX preset.' It does not explain track_index or fx_index, so it does not compensate for the schema gap.

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 exactly what happens: REAPER cannot save a named FX preset and the tool always returns an error. It also names the sibling get_track_fx_chunk as the alternative for capturing FX state, so it is distinguishable from functional FX preset siblings like set_fx_preset.

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 explicitly tells the agent not to use this tool for its nominal purpose and directs it to get_track_fx_chunk instead. The when-not condition and alternative are unambiguous.

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