ableton-mcp

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apply_midi_diatonic_chord_quality

Destructive

Rebuild MIDI chords diatonically in Ableton Live by planning or atomically applying guarded functional-harmony recipes, inversions, voicings, slash basses, and retained voices.

Instructions

Plan or atomically apply guarded functional-harmony chord rebuilding with per-onset functions, recipes, inversions, voicing modes, slash basses, stable retained voices, and verified additions/removals.

Input Schema

Name	Required	Description
`mode`	Yes
`clipId`	Yes	list_clips Session ID or supported list_arrangement_clips ID.
`dryRun`	No	False executes with token and hash.
`noteIds`	Yes	Unique stable note IDs at complete chord onsets.
`trackId`	Yes	ID from list_tracks.
`planHash`	No	Plan hash.
`chordSize`	No	Exact voicing recipe. Triad, seventh, and ninth stack thirds from Live's scale; suspended, added-tone, and dominant recipes use their named literal intervals, with tensions voiced above the chord.
`chordSizes`	No	One exact voicing recipe for each ordered onset.
`inversions`	No	Optional inversion steps for each ordered onset; zero keeps root position.
`bassDegrees`	No	Optional Live scale degree for one added slash-bass voice below each ordered onset.
`rootDegrees`	Yes	One root degree from Live's current scale for each ordered onset.
`voicingModes`	No	Optional deterministic voicing mode for each ordered onset.
`confirmationToken`	No	Single-use plan token.
`harmonicFunctions`	No	Optional harmonic function for each ordered onset; secondary-dominant root degrees name tonicized targets.
`expectedStateVersion`	Yes	Observed stateVersion.

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

Changed3 schema fields changedv0.3.1Oct 23, 2026

changedInput schema / properties / clipId / description

Previous value: -"Session ID from list_clips; Arrangement ID from list_arrangement_clips where supported."New value: +"list_clips Session ID or supported list_arrangement_clips ID."

removedOutput schema / additionalProperties
```
Removed value: -true
```

addedOutput schema / anyOf

Added value: +[
+  {
+    "oneOf": [
+      {
+        "properties": {
+          "confirmation": {
+            "properties": {
+              "expiresAt": {
+                "type": "number"
+              },
+              "planHash": {
+                "pattern": "^[a-f0-9]{64}$",
+                "type": "string"
+              },
+              "token": {
+                "minLength": 1,
+                "type": "string"
+              }
+            },
+            "required": [
+              "token",
+              "planHash",
+              "expiresAt"
+            ],
+            "type": "object"
+          },
+          "dryRun": {
+            "const": true
+          },
+          "plan": {
+            "type": "object"
+          }
+        },
+        "required": [
+          "dryRun",
+          "plan",
+          "confirmation"
+        ],
+        "type": "object"
+      },
+      {
+        "properties": {
+          "dryRun": {
+            "const": false
+          },
+          "operationOutcome": {
+            "properties": {
+              "evidence": {
+                "items": {
+                  "type": "string"
+                },
+                "type": "array"
+              },
+              "reason": {
+                "type": "string"
+              },
+              "schemaVersion": {
+                "const": 1
+              },
+              "status": {
+                "enum": [
+                  "applied",
+                  "outcome_unknown",
+                  "postconditions_failed",
+                  "pending_postconditions",
+                  "pending_user_action"
+                ]
+              }
+            },
+            "required": [
+              "schemaVersion",
+              "status",
+              "reason",
+              "evidence"
+            ],
+            "type": "object"
+          }
+        },
+        "required": [
+          "dryRun",
+          "operationOutcome"
+        ],
+        "type": "object"
+      }
+    ],
+    "properties": {
+      "dryRun": {
+        "type": "boolean"
+      }
+    },
+    "required": [
+      "dryRun"
+    ],
+    "type": "object"
+  },
+  {
+    "properties": {
+      "error": {
+        "properties": {
+          "message": {
+            "type": "string"
+          },
+          "outcome": {
+            "enum": [
+              "unknown",
+              "not_executed"
+            ]
+          }
+        },
+        "required": [
+          "message",
+          "outcome"
+        ],
+        "type": "object"
+      }
+    },
+    "required": [
+      "error"
+    ],
+    "type": "object"
+  }
+]

Changed7 schema fields changedv0.3.0Oct 19, 2026

changedInput schema / properties / clipId / description

Previous value: -"Stable clip ID: track-N:clip-M from list_clips, or track-N:arrangement-clip-M from list_arrangement_clips for tools that support Arrangement clips."New value: +"Session ID from list_clips; Arrangement ID from list_arrangement_clips where supported."

changedInput schema / properties / confirmationToken / description

Previous value: -"Short-lived, single-use token returned by the matching dry run."New value: +"Single-use plan token."

changedInput schema / properties / dryRun / description

Previous value: -"Omit or true to return a plan; false requires a valid confirmationToken."New value: +"False executes with token and hash."

changedInput schema / properties / expectedStateVersion / description

Previous value: -"Exact stateVersion observed immediately before planning."New value: +"Observed stateVersion."

changedInput schema / properties / planHash / description

Previous value: -"Hash returned by the matching dry run."New value: +"Plan hash."

changedInput schema / properties / trackId / description

Previous value: -"Stable track ID returned by list_tracks."New value: +"ID from list_tracks."

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "additionalProperties": true,
+  "type": "object"
+}

First observedv0.1.0Sep 23, 2026

TDQS

B3.4/5.0

Behavior4/5

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

Annotations already declare destructive=true, readOnly=false and idempotent=false, so safety is largely covered. The description adds genuine value beyond that: atomicity ("atomically apply"), a guard/verification step ("verified additions/removals"), and preservation of untouched material ("stable retained voices"). It stops short of stating permission or failure/precondition behavior.

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?

It is a single sentence with the action front-loaded, and nothing is repeated. The feature enumeration is dense and reads more as a keyword list than prose, which slightly hurts scanability, but there is no filler.

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

Completeness3/5

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 annotations cover the destructive profile. For a 15-parameter, 6-required guarded mutation, though, the description never explains the plan/apply verification flow (expectedStateVersion, planHash, confirmationToken) or its relation to the plan_ sibling tool, leaving the agent to reconstruct the workflow from the schema alone.

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 93%, so the schema already documents nearly every parameter. The description's enumeration (per-onset functions, recipes, inversions, voicing modes, slash basses) maps onto harmonicFunctions, chordSize/chordSizes, inversions, voicingModes and bassDegrees but adds little syntax or semantics beyond the schema. Baseline 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 clear verb pair ("Plan or atomically apply") and a specific resource ("functional-harmony chord rebuilding"), so an agent knows it edits chord qualities rather than the harmony/transposition siblings. It does not, however, distinguish itself from close siblings like plan_midi_diatonic_chord_quality, apply_midi_diatonic_harmony, or apply_midi_scale_chord_remapping, and terms like "guarded" and "rebuilding" remain jargon.

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

Usage Guidelines2/5

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

The phrase "Plan or atomically apply" hints at a two-phase dry-run/commit workflow, but the description gives no explicit when-to-use conditions, prerequisites, or pointer to an alternative sibling. The agent is left to infer which tool handles which harmony scenario.

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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