ableton-mcp

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plan_midi_chord_voice_leading

Read-onlyIdempotent

Plans deterministic octave-only voice leading across complete chord onsets, anchored to the first chord, so MIDI chord progressions can be adjusted with predictable voice motion.

Instructions

Plan deterministic octave-only voice leading across complete chord onsets, anchored to the first chord.

Input Schema

Name	Required	Description
`mode`	Yes	Lead every voice by octave or keep each chord's current bass fixed.
`clipId`	Yes	list_clips Session ID or supported list_arrangement_clips ID.
`noteIds`	Yes	Unique stable note IDs across complete ordered chord onsets.
`trackId`	Yes	ID from list_tracks.
`maxPitch`	Yes
`minPitch`	Yes

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: +[
+  {
+    "properties": {
+      "clipId": {
+        "type": "string"
+      },
+      "context": {
+        "type": "object"
+      },
+      "plan": {
+        "properties": {
+          "changes": {
+            "items": {
+              "type": "object"
+            },
+            "type": "array"
+          },
+          "newNotes": {
+            "items": {
+              "properties": {
+                "duration": {
+                  "type": "number"
+                },
+                "pitch": {
+                  "maximum": 127,
+                  "minimum": 0,
+                  "type": "integer"
+                },
+                "start": {
+                  "type": "number"
+                },
+                "velocity": {
+                  "maximum": 127,
+                  "minimum": 0,
+                  "type": "integer"
+                }
+              },
+              "required": [
+                "pitch",
+                "start",
+                "duration",
+                "velocity"
+              ],
+              "type": "object"
+            },
+            "type": "array"
+          },
+          "noteIds": {
+            "items": {
+              "type": "integer"
+            },
+            "type": "array"
+          },
+          "notes": {
+            "items": {
+              "properties": {
+                "duration": {
+                  "type": "number"
+                },
+                "pitch": {
+                  "maximum": 127,
+                  "minimum": 0,
+                  "type": "integer"
+                },
+                "start": {
+                  "type": "number"
+                },
+                "velocity": {
+                  "maximum": 127,
+                  "minimum": 0,
+                  "type": "integer"
+                }
+              },
+              "required": [
+                "pitch",
+                "start",
+                "duration",
+                "velocity"
+              ],
+              "type": "object"
+            },
+            "type": "array"
+          },
+          "preservedNotes": {
+            "items": {
+              "type": "object"
+            },
+            "type": "array"
+          }
+        },
+        "required": [],
+        "type": "object"
+      },
+      "stateVersion": {
+        "minimum": 1,
+        "type": "integer"
+      },
+      "trackId": {
+        "type": "string"
+      }
+    },
+    "required": [
+      "stateVersion",
+      "trackId",
+      "clipId",
+      "context",
+      "plan"
+    ],
+    "type": "object"
+  },
+  {
+    "properties": {
+      "error": {
+        "properties": {
+          "message": {
+            "type": "string"
+          },
+          "outcome": {
+            "enum": [
+              "unknown",
+              "not_executed"
+            ]
+          }
+        },
+        "required": [
+          "message",
+          "outcome"
+        ],
+        "type": "object"
+      }
+    },
+    "required": [
+      "error"
+    ],
+    "type": "object"
+  }
+]

Changed3 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 / 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

A3.5/5.0

Behavior4/5

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

The annotations already establish that this is a read-only, idempotent, non-destructive operation. The description adds meaningful behavioral detail beyond annotations by specifying deterministic octave-only motion, complete chord onsets, and anchoring to the first chord. It does not explain return shape, but an output schema exists.

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?

The definition is a single tightly packed sentence with the core operation and key qualifiers front-loaded. Every phrase contributes to scope or behavior, with 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?

For a complex planning tool with six required parameters, the description communicates the core algorithm and scope but omits usage guidance relative to sibling planners and the apply step. Annotations and the output schema cover safety and return values, so the remaining gap is mainly routing and parameter guidance.

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 coverage is 67%, with descriptions for mode, clipId, noteIds, and trackId, while minPitch and maxPitch rely on schema constraints alone. The description adds conceptual constraints such as octave-only motion and complete chord onsets, but it does not directly explain parameter usage or compensate for the undocumented pitch-range parameters.

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?

The description states a specific verb and resource: 'Plan ... voice leading' with precise qualifiers ('deterministic octave-only', 'complete chord onsets', 'anchored to the first chord'). It is clearly not a generic voice-leading tool, but it does not explicitly distinguish itself from nearby siblings such as plan_midi_chord_inversion or apply_midi_chord_voice_leading.

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 description implies the tool is for planning octave-only voice leading, but it gives no explicit when-to-use guidance, no exclusions, and no alternatives. It does not say when an agent should choose this over apply_midi_chord_voice_leading or other chord-planning siblings.

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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