PostFader

Change any combination of one Channel Rack channel's settings in one call. Set only the fields to change: volume, pan, mute, solo, pitch, name and color, mixer routing, and exclusive selection. Requires write mode (session_set_write_mode). Writes run in that order, each read back on a later FL tick with its own receipt; verified is true only when every write verified. Non-atomic: earlier writes remain if a later one fails. Use plugin_set_parameter for the channel's instrument, channel_set_steps for its step grid, and piano_roll_write_notes for its notes. Does not save.

Turn step-sequencer cells on or off for one channel in the current pattern. Requires write mode and a fresh channel_get_steps read: the edit refuses if the grid no longer matches expected_digest, so nothing is overwritten blindly. Each changed cell is read back on a later tick and reported. Use piano_roll_write_notes for pitched notes and lengths. Does not save.

Generate a bass part that follows a Roman-numeral progression, without touching FL. Deterministic for a given seed. Use the same progression and key as compose_chord_progression so the parts agree. Returns a note sequence in beats for piano_roll_write_notes or compose_export_midi.

Generate voice-led chords from Roman numerals in a key, without touching FL. Deterministic: the same inputs give the same notes. Returns a note sequence in beats with a digest. Write it with piano_roll_write_notes, export it with compose_export_midi, or pass the progression to compose_bassline.

Generate kick, snare, and hat patterns in a style, without touching FL. Deterministic for a given seed. Without drum_map it uses General MIDI drum notes, which many FL kits do not follow; read the kit's pads with plugin_get_pad_map and plan sounds first so hits land on the right pads. Returns a note sequence in beats for piano_roll_write_notes.

Write note sequences to a standard Type-1 MIDI file and verify it. Writes a local file only; the FL project is unchanged. Re-opens and parses the file to verify its digest, tracks, and events. Refuses to replace an existing file unless overwrite=true. The user can drag the file into FL; use piano_roll_write_notes to put notes in the open project instead.

Generate a scale-aware melody within a register, without touching FL. Deterministic for a given seed; change the seed for alternatives. Returns a note sequence in beats. Fit the register to the chosen sound (sound_plan_palette) before writing it with piano_roll_write_notes.

Read a peak watch's status and cumulative per-track peaks so far. Read-only; the watch keeps running. Returns each track's maximum peak, clipping frame count, and last fader reading. Watches are process-local and end when the MCP server restarts.

Read one mixer track's full state: level, pan, effects, EQ, and sends. Read-only. Returns the fader in normalized and dB form, pan, stereo separation, mute/solo/arm, name, color, effect slots, the built-in three-band EQ, and outgoing sends with their levels. Read it before mixer_set_track to supply current values as expected_before guards.

List mixer tracks with names, levels, mute/solo state, and loaded effects. Read-only. Index 0 is Master. Use it to find track indices and effect slots before mixer_set_track or plugin tools; use mixer_get_track for one track's built-in EQ and outgoing sends, and mixer_start_peak_watch for levels over time.

Propose dB fader moves that bring each watched track to a target peak. Read-only: nothing is applied. Returns mixer_volume_db operations with expected_before guards from the watch, the watch's session_fingerprint, a rationale per track, and the tracks it skipped (muted, silent, Master, or already within 0.5 dB). Review them, then pass operations and session_fingerprint to project_apply_edits. Re-watch and re-bounce after applying.

Change any combination of one mixer track's settings in one call. Set only the fields to change: name, color, volume (normalized or dB), pan, stereo separation, mute, solo, record arm, built-in EQ bands, sends, and whether it is the active track. Requires write mode (session_set_write_mode). Writes run in that order, each read back on a later FL tick with its own receipt; verified is true only when every write verified. Non-atomic: earlier writes remain if a later one fails, and an unknown outcome stops the rest. Use plugin_set_parameter for effect parameters and project_apply_edits for sever…

Start sampling mixer peak meters while the user plays the song. Runs in the background in this MCP process and returns its first frame and a watch_id. Ask the user to play the section to measure, then read it with mixer_get_peak_watch or end it with mixer_stop_peak_watch. Changes no project state. Meter peaks are post-fader samples, not audio analysis; use the watch with mixer_plan_gain_staging to propose fader moves.

Stop a peak watch early and return its final per-track aggregate. Changes no project state. A stopped watch can still be read and used by mixer_plan_gain_staging.

Create a pattern: find the first empty one, select it, name it, and size it. Requires write mode. Searches from start_pattern_number for a pattern FL reports as empty, then selects it and sets its name, optional color, and length, verifying each step. outcome names the first step that did not verify. Use pattern_set to change an existing pattern. Does not save.

List the project's patterns with name, color, length, and which is current. Read-only. Also reports whether each pattern is FL's default empty pattern. Use pattern numbers with pattern_set, channel_get_steps, and the piano_roll tools; use pattern_create to make a new named pattern.

Rename, recolor, resize, or select one existing pattern in one call. Set only the fields to change. Requires write mode. Writes run in the order name/color, length, then selection, each read back on a later tick with its own receipt; verified is true only when all verified. Non-atomic. Use pattern_create for a new empty pattern. Does not save the project.

Read the notes of one channel in one pattern: pitch, timing, and expression. Opens that score in FL's Piano Roll (which changes focus) but never changes notes or enables writes. Needs the piano_roll_setup step done once. Read before composing around existing material or transforming it. Follow next_offset to page; a selected_only page can be empty and still have a next_offset.

Prepare the one-time Piano Roll scripting setup that note tools need. status reports readiness without writing files. prepare writes the Postfader Apply script into FL's Piano Roll scripts folder; the user must then run it once from FL's Piano Roll menu. confirm with confirm_user_ran_script=true arms this MCP process. Writes no notes. Reuse the setup for the rest of the session.

Quantize, transpose, humanize, duplicate, delete, or clear existing notes. Applies to the selected notes or the whole score of one channel in one pattern. Requires write mode and the one-time piano_roll_setup; read the notes first with piano_roll_read_notes. delete and clear remove notes in scope. Works like piano_roll_write_notes: a dispatch is not proof, so inspect the evidence. Use piano_roll_write_notes to add new notes.

Write notes into one channel's Piano Roll score in a pattern. Requires write mode and the one-time piano_roll_setup. Writes a local script, selects the channel and pattern, and triggers FL's run-last-script shortcut, then checks the selected target, the script's application, and persistence. A dispatch alone is not proof the notes landed: inspect the returned evidence, and treat a missing receipt as an unknown outcome, not a reason to retry. Use piano_roll_transform_notes to edit existing notes. Does not save the project.

Add named section markers (Intro, Verse, Drop) to the Playlist timeline. Requires write mode. FL lets PostFader read marker names back but not their times, so the receipt verifies the new names and reports times as unverified. Does not save the project.

Read the Playlist's current time selection and the project PPQ. Read-only. Returns the raw selection endpoints with validity and consistency evidence. PPQ is ticks per quarter note; the endpoints are not converted to bars and are not guaranteed render limits, so check the evidence before relying on them. Use project_get_summary for the playback position.

List every Playlist track with its name, color, and mute/solo/selection. Read-only. Playlist track indices are one-based. Use them with playlist_set_track. Clips on the Playlist are not readable through FL's scripting API.

Rename, recolor, mute, solo, or select one Playlist track in one call. Set only the fields to change. Requires write mode. Name and color are written first, then mute/solo/selection, each read back on a later tick with its own receipt; verified is true only when both verified. Playlist clips cannot be created or moved through FL's scripting API. Does not save the project.

Read an instrument's drum pads: MIDI note, color, and empty/muted state. Read-only. Read it before writing drums to a non-General-MIDI kit so each hit lands on the right pad; sound selection and the inspect_drum_map run operation turn these pads into the drum_map that compose_drums takes. complete is false when FL did not report every pad.

List the instruments and effects in FL's native Add menu (macOS only). Opens and closes the menu, which briefly changes focus; changes no project state. Reports exact loadable names and whether each is an instrument or an effect, for plugin_load. Menu presence is not proof of licensing or an exhaustive install scan.

List every loaded mixer effect and Channel Rack instrument as a target. Read-only. Each entry carries the target object that the other plugin_* tools take (mixer_effect with track and slot, or channel_generator with a channel index), the plug-in's reported name, and its parameter count. Use atlas_match_loaded to identify products, and plugin_list_parameters to see a plug-in's controls.

List a loaded plug-in's real controls with their current values and text. Read-only. FL reports a padded parameter count for VST plug-ins, often thousands of empty slots; this walks the range inside FL and returns only real controls, each with its index, name, normalized value, and display text (which identifies unnamed controls). Check truncated before treating the list as complete. Use the indices, names, or display text with plugin_set_parameter.

Read a page of a loaded plug-in's preset names, its preset count, and current preset. Read-only. Returns FL's authoritative preset_count, one page of names with their indices (follow next_start for more), and, unless include_current is false, the current preset with an index only when it is unique. Use a name or index from this list with plugin_select_preset; use sound_plan_palette to choose sounds across several roles.

Add one instrument (new channel) or mixer effect from FL's Add menu (macOS). Use an exact name from plugin_list_available. Requires write mode; an effect load first selects its mixer track. Returns the new channel or effect slot as a target for plugin_select_preset or plugin_set_parameter. If the outcome is unknown, inspect plugin_list_loaded before trying again. Windows insertion is not implemented. Does not save the project.

Load a known preset on one mixer effect or Channel Rack instrument. Supply an exact name and/or index from plugin_list_presets. Requires write mode. FL steps through presets to reach the target, which changes the sound through intermediate presets, bounded by max_navigation_steps; the landed preset's identity is read back. Inspect verified and warnings. Use sound_apply_palette for planned multi-role choices. This selects a preset; it does not set a parameter or load a new plug-in (plugin_load).

Set one plug-in parameter by display value, option text, or raw 0..1 value. Supply exactly one value form. display_value searches the control until its own display reads the number asked for, so no unit curve is guessed; use it for anything with units (Hz, dB, ms, %). option sets a word-valued control (Key, Scale, Mode) by sweeping it, which moves the control while it looks; the result lists every option found, and an unknown option restores the original value before the error. normalized_value writes 0..1 directly. Requires write mode. Read controls with plugin_list_parameters first. Inspect…

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.

Turn processing goals into concrete settings for effects that are loaded. Read-only: inspects loaded effects once and returns a plan of semantic actions, each naming the effect, control, and value, plus what could not be resolved and why. Goals and strength produce first-pass settings; explicit controls override them. Review the plan, then apply it unchanged with processing_apply, or use the plan_processing operation inside run_execute. Re-bounce and listen before refining.

Apply edits you have already decided, across several targets, in one call. Each item sets an absolute value on a mixer track, channel, pattern, Playlist track, plug-in parameter, or the tempo, in order, after one session check; mixer_plan_gain_staging returns items in this form. For several fields of one target, its setter (mixer_set_track, channel_set) is simpler. It does not apply plans: processing_apply, sound_apply_palette, and review_apply_revision apply their own planner's result, and run_execute runs multi-step work. Requires write mode. Every attempted item gets its own later-tick rec…

Read FL's undo history: position, count, next undo hint, and dirty state. Read-only. Call it before project_step_history to see what an undo or redo would move to, and pass its position, count, or dirty flag as that call's expected_before guard.

Read the open project's metadata, counts, dirty state, and transport. Returns the title, tempo, PPQ, mixer/channel/pattern/Playlist counts, the undo position, dirty state, the connection with its session_fingerprint, and the transport (playing, recording, loop mode, position, metronome, precount, time signature). Read-only. Use it for overall context and the transport state before transport_set; use the area list tools (mixer_list_tracks, channel_list, pattern_list, playlist_list_tracks) for target details.

Undo or redo one step of FL Studio's project history and verify the move. Requires write mode (session_set_write_mode). Moves exactly one step and reads FL's history position back on a later tick; the receipt reports the position before and after. FL's history covers every project change, not only PostFader's, so read project_get_history first and guard with expected_before. Does not save the project.

Cancel a render job: stop monitoring it and the process it started. On macOS the separate FL renderer may stay open after cancellation; check render_get_job for the final status.

Read a render job's status and, once ready, its decoded WAV details. Read-only. output_ready means the WAV decoded fully and is usable; completed also means the FL process has exited.

Render a saved .flp to a WAV with FL's command-line exporter, as a background job. Starts a separate FL process; the open project and its unsaved changes are not included, because only saved state renders. Returns a job_id at once; poll render_get_job for the output. Jobs live in this MCP process. Use the finished WAV with the audio_* or review_* tools.

Apply the revision plan returned by review_plan_revision to the project. Takes only a plan recorded in this Review Session and runs it through a Production Run. Needs authorized_to_modify=true from a request to revise in this task. Runs one readiness preflight, enables write mode for the run, applies the plan's operations with receipts, and releases write mode. Stops on a blocker or unknown outcome. Then ask the user for a new export (review_get view=export_request) and compare it with review_compare.

Validate exported audio files and attach them to a Review Session. Paths must be explicit caller-selected files (audio_list_recent_bounces can find them). Checks format, size, stability, hashes, and alignment evidence; rejects directories, changing files, and duplicates. Changes no project state. Evaluate the attached full mix with review_evaluate.

Compare the bounces before and after a revision against its objective. Reads the files only. Reports what changed toward or away from the revision objective, using matching export settings. A better measurement is not producer approval; ask the user and record it with review_record_feedback.

Delete one Review Session's stored record after the user asks to. Removes the session's metadata from the local store. Audio files and the FL project are untouched. Cannot be undone.

Measure an attached bounce as a whole and section by section, with findings. Reads the files only; makes no FL changes. Returns findings tied to measurements and sections that review_plan_revision can address. Measurements support decisions; they never establish the producer's approval, which only review_record_feedback records.

Write a Review Session's delivery manifest to new JSON or Markdown files. Creates new local files only and never overwrites an existing one; the FL project is not saved or changed. Preview the content first with review_get view=delivery_manifest.

Read a Review Session, its next export request, or its delivery manifest. Read-only. Use view=session to see where the review stands and what to do next; view=export_request when the user must export a new bounce, to tell them exactly what to render; view=delivery_manifest to summarize what is done and what export or import work remains. Write the manifest to files with review_export_delivery.

Compile one bounded revision plan from evaluation findings and feedback. Read-only: validates that each operation traces to a finding or feedback, respects the producer's locks on accepted sound, notes, rhythm, register, processing, level, placement, and roles, and stays within the pass limit. Records the plan in the session for review_apply_revision.

Record the producer's explicit feedback and locks in a Review Session. Feedback outranks measurements. Locks protect accepted elements (sound, notes, rhythm, register, processing, level, placement, role) from later revisions. Changes no project state. Silence and good measurements never count as approval. Use sound_record_feedback for feedback on a sound palette.

Start a Review Session for the result of one completed Production Run. The session keeps the run's outputs, palette, processing receipts, and section map as evidence for evaluating bounces of that work. Changes no project state. Next, have the user export a full mix and attach it with review_attach_assets. Sessions are process-local unless persist_session is set.

Stop a Review Session so no further revision work happens. Completed project changes stay; nothing is undone. The session's record remains readable with review_get; use review_delete to remove it.

Resume a stopped or blocked Production Run, or change its unexecuted remainder. Use it after the user's follow-up or after fixing a blocker. Completed operations and their receipts are kept and never re-run; an operation with an unknown outcome is never replayed. Write mode is enabled for the run and released afterwards, like run_execute. Find saved runs with run_list.

List Production Run operations and return exact schemas for the ones named. Read-only and offline. Plan schemas in run_execute, run_validate, and run_continue name operations without listing their fields, so call this first with the operations you will use (up to eight per call). Operations cover composing, writing notes, patterns, markers, automation, direct edits, sound palettes, presets, drum kits, effect processing, and review steps; save, render, plug-in insertion, and Playlist clips are refused.

Run a multi-step production plan, such as writing a chorus, as one task. The main path for work that spans several kinds of operation, such as composing, writing notes, arranging, choosing sounds, and processing: it validates the whole plan, checks readiness, enables write mode once for the run, executes operations in order with per-operation receipts, and releases write mode when finished. For edits already decided, use the setters or project_apply_edits; to apply one result of processing_plan, sound_plan_palette, or review_plan_revision, use that area's apply tool. It stops at a blocker or …

Read a run's status, generated outputs, and per-operation receipts. Read-only; works for current runs and runs saved before an MCP restart. Use it to inspect what a run did, which operation blocked, and the outputs (note sequences, palettes, plans) that later operations or reviews can reference.

List recent Production Runs saved on this computer, newest first. Read-only; executes nothing. Use it after an MCP restart to find a run_id for run_get or run_continue.

Stop a run so no further operations execute. Completed changes stay in the project; nothing is undone (use project_step_history to undo). Returns the run's final state and receipts.

Dry-run a Production Run plan against the live project without changing it. Checks the plan's structure, operation order, capabilities, targets, and scope rules against the current FL session and returns whether it is executable, its blockers, and a plan digest. include_readiness adds the setup scorecard (Piano Roll setup, missing plug-ins, manual steps). Use it only when the user wants a plan reviewed or a diagnosis: run_execute performs the same checks itself, so do not validate before every run.

Report which FL Studio integration paths work in this bridge session. Returns the connection (FL version, protocol, write mode, and the current session_fingerprint) and, for each capability, whether it is direct, partial, unavailable, or unvalidated. Read-only. Call it when a tool is refused or before planning work that depends on a capability; use project_get_summary for the open project's contents.

Turn write mode on or off for this bridge session without restarting FL. Setters (mixer_set_track, channel_set, plugin_set_parameter and the other tools that change the project directly) refuse until write mode is on. run_execute, run_continue, processing_apply, sound_apply_palette, and review_apply_revision enable it for their own work. Enabling requires confirm_user_present=true; the user's request to edit is that confirmation, so do not ask separately. The result is verified with a fresh handshake. Changes no project value, applies only to this session, and is never saved. Disable it when …

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.

Report the local sound-selection history: location, health, and record counts. Read-only. History stores accepted and rejected choices on this computer to steer later palettes. Use sound_reset_history only when the user asks to clear it.

Read the pool of loaded instruments and their presets that palettes choose from. Read-only. Returns each loaded instrument (and effects when requested) with its preset names, current preset, drum pad map, and Atlas knowledge. sound_plan_palette reads this inventory itself, so call it only to show the user what is available. Atlas-only products are recommendations, not loaded sounds.

Look up a previously planned sound palette by its palette_id. Read-only. Palettes live in this MCP process; an expired or unknown ID is reported in the result rather than raised as an error, so plan again if it is gone.

Choose an instrument and preset for each musical role from loaded sounds. Read-only: reads the live inventory and returns deterministic assignments with score reasons and a palette_id, without changing FL or history. With base_palette_id it plans a variation for a later section instead, keeping the base palette's anchors except replace_roles. Explicit roles and preferences override genre defaults. Review the plan, then apply it with sound_apply_palette before writing notes, so parts fit the chosen sounds.

Record the user's explicit verdict on a palette so future picks follow it. Scope the verdict with palette_id and optionally role_id or assignment_id; descriptors name qualities the user wants more or less of. May write local history according to the request's persistence settings; never changes the FL project. Never infer acceptance from silence. Feedback does not generate a replacement: use sound_plan_palette with base_palette_id for that.

Delete the local sound-selection history after the user asks to. Removes the bounded history records that steer future palettes. Cannot be undone. The FL project and its presets are unchanged.

Change playback, recording, tempo, loop mode, and other transport settings. Set only the fields to change; each is an absolute state, never a toggle. Requires write mode. Writes run in a fixed order so one call can stop, adjust, and restart: stop/pause and recording-off first; then tempo, time signature, loop mode, metronome, precount, and position; then recording-on; then playback last. Each write gets its own later-tick receipt, and verified is true only when all of them verified. Non-atomic: earlier writes remain if a later one fails. Read the current state with project_get_summary. Does n…