fx_add

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It details the underlying REAPER API call (TrackFX_AddByName), explains fuzzy resolution, notes that plugin format cannot be selected, and warns that REAPER's 'vst:'/'vst3:' prefixes and raw .dll filenames fail. This is highly transparent about how the tool behaves.

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 front-loaded with the main purpose, followed by a well-structured paragraph explaining naming nuances, and ends with a clear Args list. Although it is longer than typical descriptions, every sentence carries essential information for correct usage, making it appropriately sized and well organized.

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?

Given the tool's complexity (fuzzy naming, format ambiguity) and lack of annotations/output schema, the description covers all critical aspects needed for correct invocation. It explains what failures look like, how to avoid them, and how parameters should be formed. Nothing essential is missing.

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 so thoroughly: 'track_index' is defined as '0-based track index', and 'fx_name' is defined as 'Bare plugin name' with concrete examples and a detailed explanation of what formats are acceptable. This adds significant meaning beyond the bare 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 starts with 'Add FX plugin to track', which is a specific verb+resource statement that clearly states what the tool does. It also distinguishes itself from the sibling tool setup_fx_chain by noting 'Prefer setup_fx_chain for batch operations', making it clear this tool is for single operations.

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 explicitly names an alternative tool ('Prefer setup_fx_chain for batch operations') and provides extensive guidance on naming conventions, including what prefixes fail and how to interpret fx_list_installed output. This gives the agent clear direction on when to use this tool and how to avoid pitfalls.

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