ableton-mcp

Overview Schema Source Related Servers Discussions Admin

apply_midi_velocity_curve

Destructive

Plan or apply a guarded MIDI velocity curve to selected notes while preserving timing, pitch, duration, probability, and expression metadata.

Instructions

Plan or apply a guarded MIDI velocity curve while preserving timing, pitch, duration, probability, and expression metadata.

Input Schema

Name	Required	Description
`curve`	Yes	Exact crescendo, decrescendo, fixed, or repeating accent target.
`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 selected onsets.
`trackId`	Yes	ID from list_tracks.
`planHash`	No	Plan hash.
`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.

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

A3.6/5.0

Behavior4/5

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

Annotations already declare a destructive, non-idempotent mutation, so the description is not burdened with safety disclosure. It adds useful scope by saying timing, pitch, duration, probability, and expression metadata are preserved, clarifying exactly what the operation should not alter.

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 a single front-loaded sentence with no redundant restatement of schema or annotations. Every clause earns its place by naming the operation and the attributes it preserves.

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?

With complete annotations, full schema coverage, and an output schema, the description provides enough context about affected and preserved data to invoke the tool correctly. Its only notable omission is routing guidance relative to the planner sibling.

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% and documents all 8 parameters, including curve variants and the guard fields. The description adds no parameter-level meaning beyond the schema, so the baseline 3 is appropriate.

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 ('plan or apply a MIDI velocity curve') and lists preserved attributes, making the operation recognizable. However, it does not differentiate from the sibling plan_midi_velocity_curve, and 'Plan or apply' blurs whether this is the execution tool or also a planner.

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 gives no explicit when-to-use guidance, no alternatives, and no prerequisites. It does not mention plan_midi_velocity_curve or explain when dryRun/planHash/confirmationToken should be used, leaving selection to inference from the name and schema.

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

Deploy Server