PostFader V12 — FL Studio MCP Server

Overview Schema Source Related Servers Discussions Admin

audio_compare_files

Read-onlyIdempotent

Compare a candidate render with a reference, align and loudness-match them, then measure per-band differences to suggest bounded tonal adjustments for review.

Instructions

Compare a candidate render with a reference and suggest tonal adjustments.

Reads both files; changes nothing. Aligns them, matches loudness, and measures per-band differences over their common overlap. When alignment and readiness checks pass, it adds bounded review ranges per band (reduce or increase the candidate); otherwise actionable is false. Suggestions are starting points to review, not targets to apply blindly.

Input Schema

TableJSON Schema

Name	Required	Description
`max_seconds`	No	Optional shorter analysis bound in seconds; the default reads up to 600.
`candidate_path`	Yes	Absolute path to the candidate render being judged.
`reference_path`	Yes	Absolute path to the reference render.

Output Schema

TableJSON Schema

Name	Required	Default
`warnings`	No
`actionable`	Yes
`comparison`	Yes
`adjustments`	Yes
`generated_at`	Yes
`schema_version`	No	1.0
`mutations_applied`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed104 schema fields changedv11.0.2Oct 5, 2026

changedInput schema / properties / candidate_path / description

Previous value: -"Absolute path to the candidate render; reported as the target."New value: +"Absolute path to the candidate render being judged."

removedOutput schema / $defs / AlignmentConfidence / properties / basis / title
```
Removed value: -"Basis"
```
removedOutput schema / $defs / AlignmentConfidence / properties / level / title
```
Removed value: -"Level"
```
removedOutput schema / $defs / AlignmentConfidence / properties / score / title
```
Removed value: -"Score"
```
removedOutput schema / $defs / AlignmentConfidence / title
```
Removed value: -"AlignmentConfidence"
```
removedOutput schema / $defs / AlignmentReport / properties / absolute_correlation / title
```
Removed value: -"Absolute Correlation"
```
removedOutput schema / $defs / AlignmentReport / properties / analysis_rate_hz / title
```
Removed value: -"Analysis Rate Hz"
```
removedOutput schema / $defs / AlignmentReport / properties / common_coverage / title
```
Removed value: -"Common Coverage"
```
removedOutput schema / $defs / AlignmentReport / properties / common_duration_sec / title
```
Removed value: -"Common Duration Sec"
```
removedOutput schema / $defs / AlignmentReport / properties / common_frames / title
```
Removed value: -"Common Frames"
```
removedOutput schema / $defs / AlignmentReport / properties / lag_convention / title
```
Removed value: -"Lag Convention"
```
removedOutput schema / $defs / AlignmentReport / properties / lag_resolution_seconds / title
```
Removed value: -"Lag Resolution Seconds"
```
removedOutput schema / $defs / AlignmentReport / properties / max_lag_seconds / title
```
Removed value: -"Max Lag Seconds"
```
removedOutput schema / $defs / AlignmentReport / properties / method / title
```
Removed value: -"Method"
```
removedOutput schema / $defs / AlignmentReport / properties / normalised_correlation / title
```
Removed value: -"Normalised Correlation"
```
removedOutput schema / $defs / AlignmentReport / properties / peak_to_next_distinct_peak_ratio / title
```
Removed value: -"Peak To Next Distinct Peak Ratio"
```
removedOutput schema / $defs / AlignmentReport / properties / reference_alignment_source / title
```
Removed value: -"Reference Alignment Source"
```
removedOutput schema / $defs / AlignmentReport / properties / reference_common_end_sample_exclusive / title
```
Removed value: -"Reference Common End Sample Exclusive"
```
removedOutput schema / $defs / AlignmentReport / properties / reference_common_start_sample / title
```
Removed value: -"Reference Common Start Sample"
```
removedOutput schema / $defs / AlignmentReport / properties / target_alignment_source / title
```
Removed value: -"Target Alignment Source"
```
removedOutput schema / $defs / AlignmentReport / properties / target_common_end_sample_exclusive_at_reference_rate / title
```
Removed value: -"Target Common End Sample Exclusive At Reference Rate"
```
removedOutput schema / $defs / AlignmentReport / properties / target_common_start_sample_at_reference_rate / title
```
Removed value: -"Target Common Start Sample At Reference Rate"
```
removedOutput schema / $defs / AlignmentReport / properties / target_lag_samples_at_reference_rate / title
```
Removed value: -"Target Lag Samples At Reference Rate"
```
removedOutput schema / $defs / AlignmentReport / properties / target_lag_seconds / title
```
Removed value: -"Target Lag Seconds"
```
removedOutput schema / $defs / AlignmentReport / title
```
Removed value: -"AlignmentReport"
```
removedOutput schema / $defs / AnalyzerVersions / properties / alignment / title
```
Removed value: -"Alignment"
```
removedOutput schema / $defs / AnalyzerVersions / properties / dynamics / title
```
Removed value: -"Dynamics"
```
removedOutput schema / $defs / AnalyzerVersions / properties / integrated_loudness / title
```
Removed value: -"Integrated Loudness"
```
removedOutput schema / $defs / AnalyzerVersions / properties / loudness_matching / title
```
Removed value: -"Loudness Matching"
```
removedOutput schema / $defs / AnalyzerVersions / properties / pitch / title
```
Removed value: -"Pitch"
```
removedOutput schema / $defs / AnalyzerVersions / properties / spectrum / title
```
Removed value: -"Spectrum"
```
removedOutput schema / $defs / AnalyzerVersions / properties / true_peak / title
```
Removed value: -"True Peak"
```
removedOutput schema / $defs / AnalyzerVersions / title
```
Removed value: -"AnalyzerVersions"
```

addedOutput schema / $defs / AudioComparison

Added value: +{
+  "additionalProperties": false,
+  "description": "A/B measurements over the common, loudness-matched overlap.\n\n``target`` throughout is the candidate file supplied by the caller; the\nname is the measurement engine's, kept verbatim so the alignment lag\nconvention reads consistently.",
+  "properties": {
+    "alignment": {
+      "$ref": "#/$defs/AlignmentReport"
+    },
+    "analyzer_version": {
+      "type": "string"
+    },
+    "analyzer_versions": {
+      "$ref": "#/$defs/AnalyzerVersions"
+    },
+    "band_deltas": {
+      "additionalProperties": {
+        "$ref": "#/$defs/BandDelta"
+      },
+      "type": "object"
+    },
+    "centroid_hz": {
+      "$ref": "#/$defs/CentroidComparison"
+    },
+    "comparison_ready": {
+      "type": "boolean"
+    },
+    "confidence": {
+      "$ref": "#/$defs/MeasurementConfidence"
+    },
+    "interpretation": {
+      "const": "measurements_only",
+      "default": "measurements_only",
+      "type": "string"
+    },
+    "limitations": {
+      "items": {
+        "type": "string"
+      },
+      "type": "array"
+    },
+    "loudness_matching": {
+      "$ref": "#/$defs/LoudnessMatchReport"
+    },
+    "measured_at": {
+      "format": "date-time",
+      "type": "string"
+    },
+    "parameters": {
+      "$ref": "#/$defs/ComparisonParameters"
+    },
+    "reference": {
+      "$ref": "#/$defs/InputProvenance"
+    },
+    "schema_version": {
+      "const": "1.0",
+      "default": "1.0",
+      "type": "string"
+    },
+    "target": {
+      "$ref": "#/$defs/InputProvenance"
+    },
+    "target_rate_conversion": {
+      "anyOf": [
+        {
+          "$ref": "#/$defs/RateConversion"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null
+    }
+  },
+  "required": [
+    "measured_at",
+    "analyzer_version",
+    "analyzer_versions",
+    "reference",
+    "target",
+    "parameters",
+    "band_deltas",
+    "centroid_hz",
+    "alignment",
+    "loudness_matching",
+    "comparison_ready",
+    "confidence",
+    "limitations"
+  ],
+  "type": "object"
+}

removedOutput schema / $defs / BandDelta / properties / difference_db / title
```
Removed value: -"Difference Db"
```
removedOutput schema / $defs / BandDelta / properties / reference_share / title
```
Removed value: -"Reference Share"
```
removedOutput schema / $defs / BandDelta / properties / target_share / title
```
Removed value: -"Target Share"
```
removedOutput schema / $defs / BandDelta / title
```
Removed value: -"BandDelta"
```
removedOutput schema / $defs / CentroidComparison / properties / reference / title
```
Removed value: -"Reference"
```
removedOutput schema / $defs / CentroidComparison / properties / target / title
```
Removed value: -"Target"
```
removedOutput schema / $defs / CentroidComparison / title
```
Removed value: -"CentroidComparison"
```
removedOutput schema / $defs / ComparisonParameters / properties / alignment_rate_hz / title
```
Removed value: -"Alignment Rate Hz"
```
removedOutput schema / $defs / ComparisonParameters / properties / max_alignment_seconds / title
```
Removed value: -"Max Alignment Seconds"
```
removedOutput schema / $defs / ComparisonParameters / properties / max_seconds / title
```
Removed value: -"Max Seconds"
```
removedOutput schema / $defs / ComparisonParameters / title
```
Removed value: -"ComparisonParameters"
```
removedOutput schema / $defs / InputProvenance / properties / analyzed_duration_sec / title
```
Removed value: -"Analyzed Duration Sec"
```
removedOutput schema / $defs / InputProvenance / properties / analyzed_frames / title
```
Removed value: -"Analyzed Frames"
```
removedOutput schema / $defs / InputProvenance / properties / canonical_path / title
```
Removed value: -"Canonical Path"
```
removedOutput schema / $defs / InputProvenance / properties / channels / title
```
Removed value: -"Channels"
```
removedOutput schema / $defs / InputProvenance / properties / sample_rate_hz / title
```
Removed value: -"Sample Rate Hz"
```
removedOutput schema / $defs / InputProvenance / properties / sha256 / title
```
Removed value: -"Sha256"
```
removedOutput schema / $defs / InputProvenance / properties / source_duration_sec / title
```
Removed value: -"Source Duration Sec"
```
removedOutput schema / $defs / InputProvenance / properties / source_frames / title
```
Removed value: -"Source Frames"
```
removedOutput schema / $defs / InputProvenance / properties / truncated / title
```
Removed value: -"Truncated"
```
removedOutput schema / $defs / InputProvenance / title
```
Removed value: -"InputProvenance"
```
removedOutput schema / $defs / LoudnessMatchReport / properties / applied / title
```
Removed value: -"Applied"
```
removedOutput schema / $defs / LoudnessMatchReport / properties / clipped_channel_samples_after / title
```
Removed value: -"Clipped Channel Samples After"
```
removedOutput schema / $defs / LoudnessMatchReport / properties / gain_db_applied / title
```
Removed value: -"Gain Db Applied"
```
removedOutput schema / $defs / LoudnessMatchReport / properties / in_memory_only / title
```
Removed value: -"In Memory Only"
```
removedOutput schema / $defs / LoudnessMatchReport / properties / method / title
```
Removed value: -"Method"
```
removedOutput schema / $defs / LoudnessMatchReport / properties / reason_not_applied / title
```
Removed value: -"Reason Not Applied"
```
removedOutput schema / $defs / LoudnessMatchReport / properties / reference_lufs / title
```
Removed value: -"Reference Lufs"
```
removedOutput schema / $defs / LoudnessMatchReport / properties / residual_lu / title
```
Removed value: -"Residual Lu"
```
removedOutput schema / $defs / LoudnessMatchReport / properties / source_files_modified / title
```
Removed value: -"Source Files Modified"
```
removedOutput schema / $defs / LoudnessMatchReport / properties / target_lufs_after / title
```
Removed value: -"Target Lufs After"
```
removedOutput schema / $defs / LoudnessMatchReport / properties / target_lufs_before / title
```
Removed value: -"Target Lufs Before"
```
removedOutput schema / $defs / LoudnessMatchReport / properties / target_sample_peak_db_after / title
```
Removed value: -"Target Sample Peak Db After"
```
removedOutput schema / $defs / LoudnessMatchReport / properties / target_sample_peak_db_before / title
```
Removed value: -"Target Sample Peak Db Before"
```
removedOutput schema / $defs / LoudnessMatchReport / title
```
Removed value: -"LoudnessMatchReport"
```
removedOutput schema / $defs / MeasurementConfidence / properties / basis / title
```
Removed value: -"Basis"
```
removedOutput schema / $defs / MeasurementConfidence / properties / level / title
```
Removed value: -"Level"
```
removedOutput schema / $defs / MeasurementConfidence / properties / scope / title
```
Removed value: -"Scope"
```
removedOutput schema / $defs / MeasurementConfidence / properties / score / title
```
Removed value: -"Score"
```
removedOutput schema / $defs / MeasurementConfidence / title
```
Removed value: -"MeasurementConfidence"
```
removedOutput schema / $defs / RateConversion / properties / from_hz / title
```
Removed value: -"From Hz"
```
removedOutput schema / $defs / RateConversion / properties / method / title
```
Removed value: -"Method"
```
removedOutput schema / $defs / RateConversion / properties / to_hz / title
```
Removed value: -"To Hz"
```
removedOutput schema / $defs / RateConversion / title
```
Removed value: -"RateConversion"
```

addedOutput schema / $defs / ReferenceAdjustment

Added value: +{
+  "additionalProperties": false,
+  "properties": {
+    "band": {
+      "maxLength": 64,
+      "minLength": 1,
+      "type": "string"
+    },
+    "direction": {
+      "enum": [
+        "reduce_candidate",
+        "increase_candidate"
+      ],
+      "type": "string"
+    },
+    "measured_difference_db": {
+      "type": "number"
+    },
+    "rationale": {
+      "maxLength": 512,
+      "minLength": 1,
+      "type": "string"
+    },
+    "suggested_review_range_db": {
+      "maxItems": 2,
+      "minItems": 2,
+      "prefixItems": [
+        {
+          "type": "number"
+        },
+        {
+          "type": "number"
+        }
+      ],
+      "type": "array"
+    }
+  },
+  "required": [
+    "band",
+    "measured_difference_db",
+    "direction",
+    "suggested_review_range_db",
+    "rationale"
+  ],
+  "type": "object"
+}

removedOutput schema / description

Removed value: -"A/B measurements over the common, loudness-matched overlap.\n\n``target`` throughout is the candidate file supplied by the caller; the\nname is the measurement engine's, kept verbatim so the alignment lag\nconvention reads consistently."

addedOutput schema / properties / actionable
```
Added value: +{
+  "type": "boolean"
+}
```

addedOutput schema / properties / adjustments

Added value: +{
+  "items": {
+    "$ref": "#/$defs/ReferenceAdjustment"
+  },
+  "type": "array"
+}

removedOutput schema / properties / alignment

Removed value: -{
-  "$ref": "#/$defs/AlignmentReport"
-}

removedOutput schema / properties / analyzer_version

Removed value: -{
-  "title": "Analyzer Version",
-  "type": "string"
-}

removedOutput schema / properties / analyzer_versions

Removed value: -{
-  "$ref": "#/$defs/AnalyzerVersions"
-}

removedOutput schema / properties / band_deltas

Removed value: -{
-  "additionalProperties": {
-    "$ref": "#/$defs/BandDelta"
-  },
-  "title": "Band Deltas",
-  "type": "object"
-}

removedOutput schema / properties / centroid_hz

Removed value: -{
-  "$ref": "#/$defs/CentroidComparison"
-}

addedOutput schema / properties / comparison

Added value: +{
+  "$ref": "#/$defs/AudioComparison"
+}

removedOutput schema / properties / comparison_ready

Removed value: -{
-  "title": "Comparison Ready",
-  "type": "boolean"
-}

removedOutput schema / properties / confidence

Removed value: -{
-  "$ref": "#/$defs/MeasurementConfidence"
-}

addedOutput schema / properties / generated_at

Added value: +{
+  "format": "date-time",
+  "type": "string"
+}

removedOutput schema / properties / interpretation

Removed value: -{
-  "const": "measurements_only",
-  "default": "measurements_only",
-  "title": "Interpretation",
-  "type": "string"
-}

removedOutput schema / properties / limitations

Removed value: -{
-  "items": {
-    "type": "string"
-  },
-  "title": "Limitations",
-  "type": "array"
-}

removedOutput schema / properties / loudness_matching

Removed value: -{
-  "$ref": "#/$defs/LoudnessMatchReport"
-}

removedOutput schema / properties / measured_at

Removed value: -{
-  "format": "date-time",
-  "title": "Measured At",
-  "type": "string"
-}

addedOutput schema / properties / mutations_applied

Added value: +{
+  "const": false,
+  "default": false,
+  "type": "boolean"
+}

removedOutput schema / properties / parameters

Removed value: -{
-  "$ref": "#/$defs/ComparisonParameters"
-}

removedOutput schema / properties / reference

Removed value: -{
-  "$ref": "#/$defs/InputProvenance"
-}

removedOutput schema / properties / schema_version / title
```
Removed value: -"Schema Version"
```

removedOutput schema / properties / target

Removed value: -{
-  "$ref": "#/$defs/InputProvenance"
-}

removedOutput schema / properties / target_rate_conversion

Removed value: -{
-  "anyOf": [
-    {
-      "$ref": "#/$defs/RateConversion"
-    },
-    {
-      "type": "null"
-    }
-  ],
-  "default": null
-}

addedOutput schema / properties / warnings

Added value: +{
+  "items": {
+    "type": "string"
+  },
+  "type": "array"
+}

changedOutput schema / required

Previous value: -[
-  "measured_at",
-  "analyzer_version",
-  "analyzer_versions",
-  "reference",
-  "target",
-  "parameters",
-  "band_deltas",
-  "centroid_hz",
-  "alignment",
-  "loudness_matching",
-  "comparison_ready",
-  "confidence",
-  "limitations"
-]New value: +[
+  "generated_at",
+  "comparison",
+  "actionable",
+  "adjustments"
+]

removedOutput schema / title
```
Removed value: -"AudioComparison"
```

Changed4 schema fields changedv11.0.1Oct 3, 2026
- removedInput schema / properties / candidate_path / title
```
Removed value: -"Candidate Path"
```
- removedInput schema / properties / max_seconds / title
```
Removed value: -"Max Seconds"
```
- removedInput schema / properties / reference_path / title
```
Removed value: -"Reference Path"
```
- removedInput schema / title
```
Removed value: -"audio_compare_filesArguments"
```
First observedv10.0.0Sep 14, 2026

TDQS

A3.8/5.0

Behavior4/5

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

Annotations already declare readOnly, idempotent, and non-destructive, so the safety profile is covered. The description adds genuine behavioral depth: alignment, loudness matching, per-band measurement over common overlap, bounded review ranges, and the condition under which actionable is false. The 'suggestions are starting points, not targets' caveat is a useful expectation-setting detail beyond structured fields.

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?

Purpose is front-loaded in the first sentence, followed by the read-only guarantee and then the mechanics. Five sentences, each carrying information, with no filler or repetition of the title.

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?

An output schema exists, so return-value explanation is not required, and the description still surfaces the key output concept (the actionable flag and bounded per-band ranges). Combined with annotations covering safety and idempotency, an agent has everything needed to call this 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 the schema already documents reference_path, candidate_path, and max_seconds in detail. The description adds no parameter-level syntax, format, or range information beyond what the schema provides, so the baseline of 3 applies.

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

Purpose4/5

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

States a specific verb and resource: compares a candidate render against a reference and outputs tonal adjustment suggestions. Clear and non-tautological. However, it never distinguishes itself from adjacent siblings like audio_analyze_file, audio_diagnose_mix, or review_compare, so sibling differentiation is absent.

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

Usage Guidelines3/5

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

Usage is implied by the candidate-vs-reference framing and it discloses that the actionable flag is true only when alignment/readiness checks pass. But it gives no explicit when-to-use vs. when-not guidance and names no alternative among the audio analysis tools, leaving selection to inference.

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

Deploy Server