ableton-mcp

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create_arrangement_midi_clip

Creates a named MIDI clip directly in an empty Arrangement interval on a MIDI track, adding up to 4096 notes relative to clip start.

Instructions

Create one named MIDI part directly in an empty Arrangement interval on an ordinary MIDI track, with up to 4096 basic notes relative to the clip start. Binds native owner/layout, rechecks at undo entry and reports actual interval, notes and timing. Preserves existing layout and processing; partial work remains without rollback or replay. Does not start playback or use Session staging. Updated bridge; all profile.

Input Schema

Name	Required	Description
`name`	Yes	Explicit name without controls.
`notes`	Yes	Initial basic MIDI notes; start/duration are relative clip beats and must fit the span.
`dryRun`	No	False executes with token and hash.
`trackId`	Yes	ID from list_tracks.
`planHash`	No	Plan hash.
`startBeats`	Yes	Absolute quarter-note song position.
`lengthBeats`	Yes	Positive span; end must be at most 1576800 beats.
`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"
+  }
+]

Addedv0.3.0Oct 19, 2026

TDQS

A3.6/5.0

Behavior4/5

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

Goes meaningfully past the annotations: it discloses non-atomic behavior ('partial work remains without rollback or replay'), that existing layout and processing are preserved, that state is rechecked at undo entry, and that the result reports the actual interval/notes/timing. The phrase 'Updated bridge; all profile' is opaque and adds no usable behavioral signal.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness3/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with the create action, which is good, but the body is dense jargon ('Binds native owner/layout', 'all profile') and the trailing 'Updated bridge; all profile' sentence carries no actionable meaning for an agent.

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?

For a 9-parameter mutation tool with an output schema (so return values need not be described), it covers preconditions, non-atomicity, state revalidation, and side effects on existing layout. The unresolved gap is the plan/confirm execution protocol implied by dryRun, planHash, and confirmationToken.

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 the baseline is 3. The description corroborates the note cap (4096) and clip-relative timing, but adds nothing about the state token, plan hash, dry-run execution mode, or the max-beat bounds — arguably the parameters most likely to be misused.

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 precise verb+resource+location: create a named MIDI part in an empty Arrangement interval on an ordinary MIDI track, with a bounded note payload. 'Does not use Session staging' and 'ordinary MIDI track' implicitly separate it from create_midi_clip and return-track variants, though no sibling is named outright.

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?

Preconditions are implied rather than prescribed: the target interval must be empty and the track must be an ordinary MIDI track, and Session staging is excluded. But there is no explicit 'use X instead when Y', and the dryRun/planHash/confirmationToken planning flow that the schema gates on is never explained in prose.

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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