ableton-mcp

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launch_clip

Destructive

Launches a Session clip or records into an empty armed slot, with state checks, optional quantization override, and dry-run confirmation support.

Instructions

Launch a Session slot. recordLengthBeats records an empty armed slot; updated bridge rechecks input, native identity and recording readiness. launchQuantization overrides once. Receipt does not prove take completion.

Input Schema

Name	Required	Description
`clipId`	Yes	list_clips Session ID or supported list_arrangement_clips ID.
`dryRun`	No	False executes with token and hash.
`trackId`	Yes	ID from list_tracks.
`planHash`	No	Plan hash.
`confirmationToken`	No	Single-use plan token.
`recordLengthBeats`	No	Fixed recording length in beats for an empty armed slot.
`launchQuantization`	No	One-shot native launch quantization choice from get_clip_timing or list_clips.launchQuantizationChoices.
`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"
+}

Changed2 schema fields changedv0.2.0Sep 30, 2026

addedInput schema / properties / launchQuantization

Added value: +{
+  "description": "One-shot native launch quantization choice from get_clip_timing or list_clips.launchQuantizationChoices.",
+  "oneOf": [
+    {
+      "type": "integer"
+    },
+    {
+      "type": "string"
+    }
+  ]
+}

addedInput schema / properties / recordLengthBeats

Added value: +{
+  "description": "Fixed recording length in beats for an empty armed slot.",
+  "exclusiveMinimum": 0,
+  "type": "number"
+}

First observedv0.1.0Sep 23, 2026

TDQS

B3.4/5.0

Behavior4/5

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

The description adds meaningful behavioral context beyond the destructive/non-idempotent annotations: it mentions bridge validation, native identity checks, recording readiness, and the important caveat that a receipt does not prove take completion. However, it does not explain what destructive side effects may occur or the dry-run/confirmation-token workflow.

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?

The description is compact and front-loads the core action in the first sentence. It is somewhat jargon-heavy, but every sentence carries some relevant information.

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 destructive 8-parameter launch tool, the description covers the main action and an important receipt caveat. It still omits practical context about the confirmation-token/dry-run path and how this differs from sibling launch or stop tools, although the schema and output schema carry much of the detail.

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 parameters are already documented. The description restates the purpose of recordLengthBeats and launchQuantization but adds little new syntax or format meaning beyond the schema itself.

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: launch a Session slot. This is clear enough to distinguish it from broad transport tools like transport_play, though it does not explicitly contrast it with the adjacent launch_scene or stop_clip tools.

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 does not say when to use this tool versus launch_scene, stop_clip, or hold_session_clip. It only gives limited parameter-specific hints about recordLengthBeats and launchQuantization, not general usage guidance or exclusions.

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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