Decent-Sampler Drums MCP Server

Instructions

Implementation Reference

• src/index.ts:630-674 (handler)

  Main execution handler for the configure_mic_routing tool. Validates input using validateMicRouting, constructs AdvancedDrumKitConfig with micBuses, generates and returns XML via generateGroupsXml.

  case "configure_mic_routing": {
    const args = request.params.arguments;
    if (!args || typeof args !== 'object' || !Array.isArray(args.micBuses) || !Array.isArray(args.drumPieces)) {
      throw new McpError(
        ErrorCode.InvalidParams,
        "Invalid arguments: expected object with micBuses and drumPieces"
      );
    }
  
    try {
      // Validate mic routing configuration
      validateMicRouting(
        args.micBuses as MicBusConfig[],
        args.drumPieces.flatMap(piece => 
          (piece.samples as Array<{ micConfig?: DrumMicConfig }>)
            .map(sample => sample.micConfig)
            .filter((config): config is DrumMicConfig => !!config)
        )
      );
  
      // Create AdvancedDrumKitConfig with mic routing
      const config: AdvancedDrumKitConfig = {
        globalSettings: {
          micBuses: args.micBuses as MicBusConfig[]
        },
        drumPieces: args.drumPieces as AdvancedDrumKitConfig['drumPieces']
      };
  
      // Generate XML with mic routing
      const xml = generateGroupsXml(config);
      return {
        content: [{
          type: "text",
          text: xml
        }]
      };
    } catch (error: unknown) {
      if (error instanceof McpError) throw error;
      const message = error instanceof Error ? error.message : String(error);
      throw new McpError(
        ErrorCode.InternalError,
        `Failed to configure mic routing: ${message}`
      );
    }
  }

• src/index.ts:284-385 (registration)

  Tool registration in ListToolsRequestSchema response, including full description and detailed inputSchema for micBuses and drumPieces configurations.

        {
          name: "configure_mic_routing",
          description: `Configure multi-mic routing with MIDI controls for drum samples.
  
  This tool will:
  - Set up individual volume controls for each mic position (close, OH L/R, room L/R)
  - Route each mic to its own auxiliary output for DAW mixing
  - Configure MIDI CC mappings for mic volumes
  - Generate proper XML structure for DecentSampler
  
  Error Handling:
  - Validates mic position assignments
  - Checks for duplicate MIDI CC assignments
  - Ensures valid output routing targets
  - Verifies bus indices are unique and valid
  - Returns specific errors for routing conflicts
  
  Success Response:
  Returns XML structure containing:
  - Configured mic bus routing
  - Volume control mappings
  - MIDI CC assignments
  - Complete routing matrix for all samples`,
          inputSchema: {
            type: "object",
            properties: {
              micBuses: {
                type: "array",
                items: {
                  type: "object",
                  properties: {
                    name: { 
                      type: "string",
                      description: "Display name for the mic (e.g., 'Close Mic', 'OH L')"
                    },
                    outputTarget: { 
                      type: "string",
                      description: "Output routing (e.g., 'AUX_STEREO_OUTPUT_1')"
                    },
                    volume: {
                      type: "object",
                      properties: {
                        default: { 
                          type: "number",
                          description: "Default volume in dB"
                        },
                        min: { 
                          type: "number",
                          description: "Minimum volume in dB (e.g., -96)"
                        },
                        max: { 
                          type: "number",
                          description: "Maximum volume in dB (e.g., 12)"
                        },
                        midiCC: { 
                          type: "number",
                          description: "MIDI CC number for volume control"
                        }
                      },
                      required: ["default"]
                    }
                  },
                  required: ["name", "outputTarget"]
                }
              },
              drumPieces: {
                type: "array",
                items: {
                  type: "object",
                  properties: {
                    name: { type: "string" },
                    rootNote: { type: "number" },
                    samples: {
                      type: "array",
                      items: {
                        type: "object",
                        properties: {
                          path: { type: "string" },
                          micConfig: {
                            type: "object",
                            properties: {
                              position: {
                                type: "string",
                                enum: ["close", "overheadLeft", "overheadRight", "roomLeft", "roomRight"]
                              },
                              busIndex: { type: "number" },
                              volume: { type: "number" }
                            },
                            required: ["position", "busIndex"]
                          }
                        },
                        required: ["path", "micConfig"]
                      }
                    }
                  },
                  required: ["name", "rootNote", "samples"]
                }
              }
            },
            required: ["micBuses", "drumPieces"]
          }
        },

• src/index.ts:307-384 (schema)

  Input schema definition specifying structure for micBuses array and drumPieces with samples and micConfig.

  inputSchema: {
    type: "object",
    properties: {
      micBuses: {
        type: "array",
        items: {
          type: "object",
          properties: {
            name: { 
              type: "string",
              description: "Display name for the mic (e.g., 'Close Mic', 'OH L')"
            },
            outputTarget: { 
              type: "string",
              description: "Output routing (e.g., 'AUX_STEREO_OUTPUT_1')"
            },
            volume: {
              type: "object",
              properties: {
                default: { 
                  type: "number",
                  description: "Default volume in dB"
                },
                min: { 
                  type: "number",
                  description: "Minimum volume in dB (e.g., -96)"
                },
                max: { 
                  type: "number",
                  description: "Maximum volume in dB (e.g., 12)"
                },
                midiCC: { 
                  type: "number",
                  description: "MIDI CC number for volume control"
                }
              },
              required: ["default"]
            }
          },
          required: ["name", "outputTarget"]
        }
      },
      drumPieces: {
        type: "array",
        items: {
          type: "object",
          properties: {
            name: { type: "string" },
            rootNote: { type: "number" },
            samples: {
              type: "array",
              items: {
                type: "object",
                properties: {
                  path: { type: "string" },
                  micConfig: {
                    type: "object",
                    properties: {
                      position: {
                        type: "string",
                        enum: ["close", "overheadLeft", "overheadRight", "roomLeft", "roomRight"]
                      },
                      busIndex: { type: "number" },
                      volume: { type: "number" }
                    },
                    required: ["position", "busIndex"]
                  }
                },
                required: ["path", "micConfig"]
              }
            }
          },
          required: ["name", "rootNote", "samples"]
        }
      }
    },
    required: ["micBuses", "drumPieces"]
  }

• src/mic-routing.ts:120-129 (helper)

  Validation helper function called by the handler to validate mic bus configurations and mic routings before generating XML.

  export function validateMicRouting(
    buses: MicBusConfig[],
    mics: DrumMicConfig[]
  ): void {
    // First validate bus configurations
    validateBusConfigurations(buses);
    
    // Then validate mic routings
    validateMicRoutings(buses, mics);
  }

• src/mic-routing.ts:2-21 (helper)

  Type definitions for MicBusConfig and DrumMicConfig used in the tool's input validation and config building.

  export interface MicVolumeConfig {
    default: number;     // dB value
    min?: number;        // Optional min dB
    max?: number;        // Optional max dB
    midiCC?: number;     // MIDI CC number for volume control
  }
  
  export interface MicBusConfig {
    name: string;          // e.g., "Close Mic", "OH L"
    outputTarget: string;  // e.g., "AUX_STEREO_OUTPUT_1"
    volume?: MicVolumeConfig;
    effects?: any[];       // Placeholder for future effects support
  }
  
  export interface DrumMicConfig {
    position: 'close' | 'overheadLeft' | 'overheadRight' | 'roomLeft' | 'roomRight';
    busIndex: number;      // Reference to which bus this mic routes to
    volume?: number;       // Optional per-sample volume adjustment
  }