fx_list_installed

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

No annotations provided, so description carries full burden. Explains the cap on the raw list and the rationale. Notes that rack plugins are detected but the MCP does not configure them, warning against routing auto-mixing through them. Also mentions user_overrides from preferences. This provides clear behavioral context for a read-only query.

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 comprehensive but somewhat lengthy, including rationale for the cap and detailed explanations. While well-structured with sections and a clear docstring, it could be slightly more concise without losing key information.

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 no output schema, the description details the return structure (all_installed, best_* picks, racks_detected, user_overrides). It explains the cap logic and parameter usage. The tool is moderately complex, and the description covers all needed aspects for an agent to use it correctly.

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%, yet the description provides detailed docstrings for both parameters: category with allowed values (eq, compressor, etc.) and full_list with explanation of when to use it. This fully compensates for the lack of schema descriptions.

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 it lists every FX plugin installed in REAPER, grouped by category. It specifies the verb 'list' and the resource 'FX plugins'. It distinguishes from siblings like fx_get_chain and other FX tools by focusing on the installed plugin inventory.

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?

Explicitly states 'Use this BEFORE running mix pipelines to know what the user has.' Provides guidance on preferring premium plugins over REAPER stock. Also explains when to use the full_list parameter: 'Only needed if you're hunting for something the built-in category rankings don't cover.'

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