ableton-mcp

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plan_scale_chord_progression

Read-onlyIdempotent

Plan exact MIDI notes for scale-degree chord progressions in Ableton Live's current key and scale, including functional harmony, block chords, arpeggios, register bounds, and voice leading.

Instructions

Plan exact MIDI notes for a scale-degree chord progression in the current Live key and scale. Supports functional harmony, block chords, grid-locked pulses, ascending or descending arpeggios, bounded register, and deterministic voice leading.

Input Schema

Name	Required	Description
`degrees`	Yes	Ordered one-based scale degrees.
`maxPitch`	Yes
`minPitch`	Yes
`velocity`	Yes
`chordBeats`	Yes	Duration and spacing of each chord in beats.
`startBeats`	Yes	First chord start in beats.
`bassDegrees`	No	Optional Live scale degree for an added bass voice below each ordered chord; null leaves that chord unchanged.
`articulation`	No
`chordRecipes`	No	Optional exact recipe for each ordered degree.
`voiceLeading`	Yes
`notesPerChord`	Yes
`harmonicFunctions`	No	Optional harmonic function for each ordered degree; secondary-dominant degrees name tonicized targets.

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedv0.3.1Oct 23, 2026

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

addedOutput schema / anyOf

Added value: +[
+  {
+    "properties": {
+      "musicalContext": {
+        "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"
+      }
+    },
+    "required": [
+      "stateVersion",
+      "musicalContext",
+      "plan"
+    ],
+    "type": "object"
+  },
+  {
+    "properties": {
+      "error": {
+        "properties": {
+          "message": {
+            "type": "string"
+          },
+          "outcome": {
+            "enum": [
+              "unknown",
+              "not_executed"
+            ]
+          }
+        },
+        "required": [
+          "message",
+          "outcome"
+        ],
+        "type": "object"
+      }
+    },
+    "required": [
+      "error"
+    ],
+    "type": "object"
+  }
+]

Changed1 schema field changedv0.3.0Oct 19, 2026

changedOutput schema / (root)

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

First observedv0.1.0Sep 23, 2026

TDQS

A3.8/5.0

Behavior4/5

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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds useful behavior beyond annotations by noting deterministic voice leading, bounded register, exact MIDI planning, and articulation modes such as block chords and arpeggios.

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 description is concise and front-loaded, first stating the purpose and then listing supported capabilities in a tight sequence. Every clause adds useful scope or feature information with no wasted wording.

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

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's complexity, nested schema, and existing output schema, the description provides a sufficient high-level orientation: it identifies the planning purpose, the current Live key/scale context, and supported musical modes. Some parameter-level details remain to the schema, but nothing critical is missing for correct high-level selection.

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 50%, so the schema documents some parameters but not all. The description adds semantic coverage for articulation modes, harmonic functions, register bounds, and voice leading, but it does not explain core required parameters such as degrees, notesPerChord, startBeats, chordBeats, velocity, or bassDegrees.

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 exact MIDI notes for a scale-degree chord progression in the current Live key and scale." This clearly distinguishes it from a clip-creating tool such as create_scale_chord_progression_clip, though it does not explicitly name any sibling tool.

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?

The description implies when to use it by focusing on planning exact MIDI notes in the current Live key and scale, rather than creating or applying notes to a clip. However, it does not explicitly state when to use this tool versus alternatives like plan_midi_diatonic_harmony, plan_scale_melody, or create_scale_chord_progression_clip.

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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