PostFader V12 — FL Studio MCP Server

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processing_apply

Destructive

Apply a processing plan to loaded FL Studio effects: checks readiness, writes each control with its verified setter, and releases write mode. Requires session fingerprint and explicit authorization.

Instructions

Apply the plan returned by processing_plan to the loaded effects.

Takes only that plan, passed back unchanged, and runs it as a
single-operation Production Run: it checks readiness, enables write mode
for the run, writes each control with its verified setter, and releases
write mode. Requires the session_fingerprint from a recent live read and
authorized_to_modify=true. Stops on an unknown or unverified outcome;
earlier settings remain. Returns the run with per-action receipts;
continue or inspect it with run_continue and run_get. To set one parameter
value directly, use plugin_set_parameter.

Input Schema

TableJSON Schema

Name	Required	Description
`plan`	Yes	The plan object returned by processing_plan, passed back unchanged.
`session_fingerprint`	Yes	Required session_fingerprint from a recent live read. The call refuses after a bridge reload or a reported project load. This is a concurrency guard, not authentication or a durable project identity.
`authorized_to_modify`	Yes	True only when the user explicitly asked for these processing changes.

Output Schema

TableJSON Schema

Name	Required	Description	Default
`run_id`	Yes
`status`	Yes
`summary`	Yes
`blockers`	No
`receipts`	No
`warnings`	No
`phase_plan`	No
`run_context`	No
`project_saved`	No
`timing_report`	No
`attempted_count`	Yes
`completed_count`	Yes
`creation_outcome`	No
`readiness_report`	No
`total_operations`	Yes
`generated_outputs`	No
`write_mode_active`	No
`rollback_attempted`	No
`session_fingerprint`	No
`project_state_digest`	No
`write_mode_enable_count`	No
`write_mode_disable_count`	No
`write_mode_shutdown_verified`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedv12.0.3Oct 5, 2026
- changedOutput schema / $defs / ProcessingPlan / properties / missing_capabilities / maxItems
```
Previous value: -128New value: +256
```
Addedv11.0.2Oct 5, 2026

TDQS

A4.8/5.0

Behavior5/5

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

Annotations already declare destructive/non-idempotent/write behavior, and the description adds real context beyond them: the write-mode enable/release sequence, failure semantics ('Stops on an unknown or unverified outcome; earlier settings remain'), the concurrency-guard meaning of session_fingerprint (refuses after bridge reload or project load, not auth), and follow-up tools run_continue/run_get. Consistent with annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with purpose, then sequence, then prerequisites, then failure behavior and alternatives. Dense and information-rich, though it runs long with several clauses that could be trimmed without losing meaning.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

A destructive multi-step mutation tool with an output schema; the description covers the operation sequence, prerequisites, failure behavior, and follow-up tools, so the agent has everything needed to call it correctly. Return values are covered by the output schema.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the baseline is 3, but the description genuinely adds meaning: 'passed back unchanged' for plan, the guard rationale for session_fingerprint, and the 'user explicitly asked' condition for authorized_to_modify. Adds value beyond the schema text, though it largely mirrors it.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Apply the plan returned by processing_plan to the loaded effects') and names the sibling it is not (plugin_set_parameter for direct single-value writes). An agent can distinguish it from processing_plan and plugin_set_parameter without opening either schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicit when-to-use ('Takes only that plan, passed back unchanged'), prerequisites (session_fingerprint from a recent live read, authorized_to_modify=true), and an explicit alternative ('To set one parameter value directly, use plugin_set_parameter'). Nothing is left to inference.

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

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