PostFader V12 — FL Studio MCP Server

by synopsys0

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Python

Local

sound_apply_palette

Destructive

Applies a sound palette in FL Studio by loading each role's preset in fixed order, stopping on unverified outcomes.

Instructions

Apply the palette returned by sound_plan_palette, loading each role's preset.

Pass the palette (or its palette_id) unchanged, the session_fingerprint
from a live read, and authorized_to_modify=true. Enables write mode for
this application, selects each assignment's preset in a fixed order with
later-tick identity readback, and stops on an unknown or unverified
outcome; earlier roles remain applied. Does not install or load plug-ins
(plugin_load). Inspect the receipts before any further attempt. Use
plugin_select_preset for one known preset without a palette.

Input Schema

TableJSON Schema

Name	Required	Description
`palette`	Yes	The palette_id from sound_plan_palette, or the full palette or variation object it returned, passed back unchanged. A variation_id is not accepted.
`role_ids`	No	Apply only these roles; empty applies every role.
`persist_history`	No	Override the palette's local-history policy for this application.
`settle_tick_limit`	No	Later FL ticks allowed for each plug-in to settle.
`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 sound changes.
`max_navigation_steps`	No	Bound on preset navigation steps per role.

Output Schema

TableJSON Schema

Name	Required	Default
`state`	Yes
`status`	Yes
`blockers`	No
`receipts`	No
`warnings`	No
`palette_id`	Yes
`schema_version`	No	1.0
`verified_count`	No
`history_written`	No
`assignment_scope`	No
`assignment_receipts`	No
`session_fingerprint`	Yes
`failed_assignment_id`	No

Schema Changelog

Changes observed during successful MCP inspections.

Addedv11.0.2Oct 5, 2026

TDQS

A4.6/5.0

Behavior5/5

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

Going well beyond the destructive/non-idempotent annotations, the description discloses that it enables write mode, applies presets in a fixed order with later-tick identity readback, halts on an unknown or unverified outcome while leaving earlier roles applied (partial-failure semantics), and advises inspecting receipts before retrying. These are non-obvious operational traits an agent needs.

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 the core action and scope, followed by prerequisites, behavior, and exclusions. Dense but essentially every sentence carries usable information, though the behavior paragraph is compact to the point of jargon ('later-tick identity readback').

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?

With an output schema present, return values need not be explained, and the annotations carry the safety profile. The description supplies the missing behavioral and routing context — prerequisites, partial-failure handling, write-mode enablement, and sibling exclusions — so an agent has everything needed to invoke it correctly.

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

Parameters3/5

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

Schema description coverage is 100%, so every parameter is already documented in the schema. The description mostly restates required inputs (palette/palette_id unchanged, session_fingerprint from a live read, authorized_to_modify=true) and adds little syntax or meaning beyond the schema, meriting the baseline 3.

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 palette returned by sound_plan_palette) and immediately scopes it to loading each role's preset. It is clearly distinguishable from planning (sound_plan_palette), inspection (sound_get_palette), and single-preset selection (plugin_select_preset).

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?

Explicitly names alternatives and their conditions: does not install/load plug-ins (plugin_load), and use plugin_select_preset for one known preset without a palette. It also states the prerequisite that the palette must originate from sound_plan_palette and be passed back unchanged, giving clear when-to-use routing.

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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