PostFader V12 — FL Studio MCP Server

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automation_record_value

Destructive

Write a control change as automation into FL Studio's arrangement by recording one value during playback with write mode and recording armed.

Instructions

Record one automation value into FL while playback and recording run.

For writing a control change into the arrangement as automation. Requires
write mode, and FL must already be playing with recording armed (set both
with transport_set). Sends one REC event for the control at the current
song position and reports the control value before and after. Whether an
automation point was created cannot be read back. To set a value without
recording it, use mixer_set_track or channel_set.

Input Schema

TableJSON Schema

Name	Required	Description
`property`	Yes	Control to record: channels support volume and pan; mixer tracks also stereo_separation.
`target_kind`	Yes	Whether target_index is a mixer track or a channel.
`allow_master`	No	Permit mixer target 0 (Master).
`target_index`	Yes	Mixer track or global channel index.
`expected_before`	No	Optional current normalized value; refuse if it changed.
`value_normalized`	Yes	Value to record, normalized 0..1.

Output Schema

TableJSON Schema

Name	Required	Default
`command`	Yes
`event_id`	Yes
`property`	Yes
`verified`	No
`warnings`	No
`applied_at`	Yes
`target_kind`	Yes
`target_index`	Yes
`project_saved`	No
`schema_version`	No	1.0
`after_normalized`	No
`controller_value`	Yes
`before_normalized`	No
`undo_point_created`	No
`session_fingerprint`	Yes
`requested_normalized`	Yes
`control_value_verified`	Yes
`capture_conditions_held`	Yes
`expected_before_applied`	Yes
`process_rec_event_result`	No
`automation_event_recorded`	No
`song_position_after_ticks`	No
`song_position_before_ticks`	No
`session_precondition_applied`	No
`automation_event_verification`	No	unavailable_no_public_point_getter

Schema Changelog

Changes observed during successful MCP inspections.

Changed32 schema fields changedv11.0.2Oct 5, 2026
- changedInput schema / properties / allow_master / description
```
Previous value: -"Explicitly permit mixer target 0."New value: +"Permit mixer target 0 (Master)."
```
- addedInput schema / properties / expected_before / description
```
Added value: +"Optional current normalized value; refuse if it changed."
```
- changedInput schema / properties / property / description
```
Previous value: -"Channel targets support volume/pan; mixer also supports stereo separation."New value: +"Control to record: channels support volume and pan; mixer tracks also stereo_separation."
```
- addedInput schema / properties / target_index / description
```
Added value: +"Mixer track or global channel index."
```
- changedInput schema / properties / target_kind / description
```
Previous value: -"Automation target namespace."New value: +"Whether target_index is a mixer track or a channel."
```
- addedInput schema / properties / value_normalized / description
```
Added value: +"Value to record, normalized 0..1."
```
- removedOutput schema / properties / after_normalized / title
```
Removed value: -"After Normalized"
```
- removedOutput schema / properties / applied_at / title
```
Removed value: -"Applied At"
```
- removedOutput schema / properties / automation_event_recorded / title
```
Removed value: -"Automation Event Recorded"
```
- removedOutput schema / properties / automation_event_verification / title
```
Removed value: -"Automation Event Verification"
```
- removedOutput schema / properties / before_normalized / title
```
Removed value: -"Before Normalized"
```
- removedOutput schema / properties / capture_conditions_held / title
```
Removed value: -"Capture Conditions Held"
```
- removedOutput schema / properties / command / title
```
Removed value: -"Command"
```
- removedOutput schema / properties / control_value_verified / title
```
Removed value: -"Control Value Verified"
```
- removedOutput schema / properties / controller_value / title
```
Removed value: -"Controller Value"
```
- removedOutput schema / properties / event_id / title
```
Removed value: -"Event Id"
```
- removedOutput schema / properties / expected_before_applied / title
```
Removed value: -"Expected Before Applied"
```
- removedOutput schema / properties / process_rec_event_result / title
```
Removed value: -"Process Rec Event Result"
```
- removedOutput schema / properties / project_saved / title
```
Removed value: -"Project Saved"
```
- removedOutput schema / properties / property / title
```
Removed value: -"Property"
```
- removedOutput schema / properties / requested_normalized / title
```
Removed value: -"Requested Normalized"
```
- removedOutput schema / properties / schema_version / title
```
Removed value: -"Schema Version"
```
- removedOutput schema / properties / session_fingerprint / title
```
Removed value: -"Session Fingerprint"
```
- removedOutput schema / properties / session_precondition_applied / title
```
Removed value: -"Session Precondition Applied"
```
- removedOutput schema / properties / song_position_after_ticks / title
```
Removed value: -"Song Position After Ticks"
```
- removedOutput schema / properties / song_position_before_ticks / title
```
Removed value: -"Song Position Before Ticks"
```
- removedOutput schema / properties / target_index / title
```
Removed value: -"Target Index"
```
- removedOutput schema / properties / target_kind / title
```
Removed value: -"Target Kind"
```
- removedOutput schema / properties / undo_point_created / title
```
Removed value: -"Undo Point Created"
```
- removedOutput schema / properties / verified / title
```
Removed value: -"Verified"
```
- removedOutput schema / properties / warnings / title
```
Removed value: -"Warnings"
```
- removedOutput schema / title
```
Removed value: -"AutomationRecordReceipt"
```
Changed7 schema fields changedv11.0.1Oct 3, 2026
- removedInput schema / properties / allow_master / title
```
Removed value: -"Allow Master"
```
- removedInput schema / properties / expected_before / title
```
Removed value: -"Expected Before"
```
- removedInput schema / properties / property / title
```
Removed value: -"Property"
```
- removedInput schema / properties / target_index / title
```
Removed value: -"Target Index"
```
- removedInput schema / properties / target_kind / title
```
Removed value: -"Target Kind"
```
- removedInput schema / properties / value_normalized / title
```
Removed value: -"Value Normalized"
```
- removedInput schema / title
```
Removed value: -"automation_record_valueArguments"
```
First observedv10.0.0Sep 14, 2026

TDQS

A4.7/5.0

Behavior5/5

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

Beyond annotations (readOnlyHint=false, destructiveHint=true, idempotentHint=false), the description discloses the concrete mechanism (sends one REC event at the current song position), the reported before/after values, and a critical limitation: whether an automation point was actually created cannot be read back. That non-verifiable write behavior is exactly the kind of trait an agent needs and annotations cannot convey.

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

Conciseness5/5

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

Front-loaded with the core action, then prerequisites, then mechanism, then limitation, then alternative. Every sentence carries distinct load with no redundancy.

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?

Prerequisites, mechanism, and the read-back limitation are all covered, and an output schema exists so return-value details need not be restated. Complete for a destructive, non-idempotent recording tool.

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 the schema already documents all six parameters including enum semantics for property and target_kind. The description adds no additional parameter-level meaning (e.g., expected_before's refuse-on-change semantics or allow_master's gating) beyond what the schema states, so the baseline 3 applies.

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+resource+scope ('Record one automation value into FL while playback and recording run') and immediately distinguishes it from sibling setters by naming mixer_set_track and channel_set as the non-recording alternative. An agent can tell this apart from transport_set, mixer_set_track, and channel_set without opening a 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?

Explicitly states the when (writing a control change into the arrangement as automation), the prerequisites (write mode required, FL must already be playing with recording armed, set via transport_set), and the alternative path (mixer_set_track/channel_set to set a value without recording). 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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