ableton-mcp

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perform_beat_repeat_fill

Destructive

Triggers a timed fill by setting an existing native Beat Repeat's Repeat On for 0.25–8 wall-clock seconds, then releases Repeat Off on Live display ticks.

Instructions

Set an existing native Beat Repeat's Repeat On for 0.25–8 requested wall-clock seconds, then release Off on Live display ticks without a client. Requires authorized playback, Repeat Off and no source recording/Repeat automation. Owns only Repeat; manual changes relinquish ownership. No beat timing, bypass or audible-result guarantee. Updated bridge; all profile.

Input Schema

Name	Required	Description
`dryRun`	No	False executes with token and hash.
`trackId`	Yes	track-N from list_tracks, return-N from get_set_mixer, or master.
`deviceId`	Yes	ID from list_devices.
`planHash`	No	Plan hash.
`durationSeconds`	Yes	Requested wall-clock duration, not beat scheduling or a hard real-time bound.
`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

A3.9/5.0

Behavior4/5

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

Adds meaningful context beyond the destructiveHint/readOnlyHint annotations: it is a timed mutation that owns only the Repeat parameter, relinquishes ownership if a user manually changes it, and makes no audible-result promise. It also notes the updated bridge/profile scope. No contradiction with 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?

Front-loaded with the action and duration bounds, then preconditions and ownership in a compact run of sentences. Dense jargon like 'Updated bridge; all profile' is slightly cryptic but not wasted bulk.

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 destructive mutation with an output schema, it covers preconditions, scope of ownership, timing caveats, and the lack of audible guarantee. It is largely complete, with only the exact relationship to sibling Beat Repeat tools left implicit.

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 already documents duration, dryRun, planHash, confirmationToken, and expectedStateVersion. The description reinforces the wall-clock interpretation and 0.25–8 range, but adds little parameter detail beyond what the schema already provides, 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 and resource: setting a native Beat Repeat's Repeat On for a bounded wall-clock duration, then releasing Off. It implies differentiation from sibling on/off and grid/interval tools through 'Owns only Repeat' and the timed release semantics, though it never names the alternatives.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives explicit preconditions: authorized playback, Repeat Off, and no source recording or Repeat automation. It also sets exclusions ('No beat timing, bypass or audible-result guarantee') but doesn't name which sibling to use for simple enable/disable or grid changes.

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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