ableton-mcp

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set_song_musical_context

Destructive

Plan or apply guarded changes to an Ableton Live song's key, scale, timing, quantization, groove, swing, or loop, with confirmation tokens to prevent unintended edits.

Instructions

Plan or apply guarded song key, scale, timing, quantization, groove, swing, or loop changes.

Input Schema

Name	Required	Description
`key`	No	Live song root, scale name, and scale mode.
`loop`	No	Arrangement loop enablement and boundaries in beats.
`dryRun`	No	False executes with token and hash.
`groove`	No	Global groove intensity and swing.
`planHash`	No	Plan hash.
`quantization`	No	Native launch and MIDI-recording quantization choices.
`timeSignature`	No	Requested native numerator and denominator.
`confirmationToken`	No	Single-use plan token.
`expectedStateVersion`	Yes	Observed stateVersion.

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: +[
+  {
+    "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"
+  }
+]

Changed15 schema fields changedv0.3.0Oct 19, 2026

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."

addedInput schema / properties / groove / description

Added value: +"Global groove intensity and swing."

removedInput schema / properties / groove / required
```
Removed value: -[]
```

addedInput schema / properties / key / description

Added value: +"Live song root, scale name, and scale mode."

removedInput schema / properties / key / required
```
Removed value: -[]
```

addedInput schema / properties / loop / description

Added value: +"Arrangement loop enablement and boundaries in beats."

removedInput schema / properties / loop / required
```
Removed value: -[]
```

changedInput schema / properties / planHash / description

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

addedInput schema / properties / quantization / description

Added value: +"Native launch and MIDI-recording quantization choices."

removedInput schema / properties / quantization / required
```
Removed value: -[]
```

addedInput schema / properties / timeSignature / description

Added value: +"Requested native numerator and denominator."

removedInput schema / properties / timeSignature / required
```
Removed value: -[]
```

changedOutput schema / (root)

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

First observedv0.1.0Sep 23, 2026

TDQS

B3.3/5.0

Behavior3/5

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

Annotations already declare destructiveHint=true and readOnlyHint=false, and the word 'guarded' hints at the plan/token safety mechanism that the schema (dryRun, planHash, confirmationToken, expectedStateVersion) supports. However, the description does not spell out what state gets overwritten, why expectedStateVersion matters, or that confirmationToken is single-use—so it adds only partial context beyond annotations.

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?

A single front-loaded sentence that wastes no words and puts the verb and scope first. It is dense to the point of being terse, but every clause earns its place.

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

Completeness2/5

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

For a destructive, nine-parameter mutation tool with nested objects and a multi-step plan/token/state-version workflow, one sentence is thin. An agent still can't tell from the description how to sequence dryRun, planHash, confirmationToken, and expectedStateVersion—the core operational flow is unexplained.

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 per-parameter meaning is already fully documented. The description's domain list (key, scale, timing, etc.) loosely corresponds to parameter groups but adds no format, unit, or constraint detail beyond the schema, so 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 specific verb pair (plan or apply) and enumerates the concrete domains affected (key, scale, timing, quantization, groove, swing, loop), which maps clearly onto song-level musical context. It is distinguishable from get_song_musical_context as the mutating counterpart, though it doesn't explicitly name that sibling or other potentially confusable tools like set_groove or set_scene_musical_context.

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?

'Plan or apply' implies a two-phase workflow, but the description never states when to use the dry-run path versus the executing path, nor when to prefer this over set_groove or set_clip_timing. Usage is implied rather than specified.

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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