analyze_transients

Instructions

Implementation Reference

• src/reaper_mcp/analysis_tools.py:197-224 (handler)

  The main handler for the 'analyze_transients' MCP tool. Renders the project to a temp WAV, uses librosa to detect onset events (note attacks, drum hits), and returns up to 100 onset timestamps.

  def analyze_transients() -> dict:
      """
      Render the project and detect transient events (note attacks, drum hits, etc.).
      Returns the count and timing of up to 100 transient onset events.
      """
      try:
          import librosa
          from reaper_mcp.render_tools import render_to_temp_file
  
          tmp = render_to_temp_file(sample_rate=44100)
          try:
              y, sr = librosa.load(tmp, sr=None, mono=True)
          finally:
              if os.path.exists(tmp):
                  os.unlink(tmp)
  
          onset_frames = librosa.onset.onset_detect(y=y, sr=sr, units="frames")
          onset_times = librosa.frames_to_time(onset_frames, sr=sr).tolist()
          capped = onset_times[:100]
  
          return {
              "success": True,
              "onset_count": len(onset_times),
              "onset_times_seconds": [round(t, 3) for t in capped],
              "note": "Showing up to 100 events" if len(onset_times) > 100 else None,
          }
      except Exception as e:
          return {"success": False, "error": str(e)}

• src/reaper_mcp/analysis_tools.py:196-197 (schema)

  The decorator-based schema/registration for the tool. No input parameters; returns a dict with success, onset_count, onset_times_seconds, and optional note.

  @mcp.tool()
  def analyze_transients() -> dict:

• src/reaper_mcp/server.py:18-28 (registration)

  The tool registration entry point: imports and calls register_tools from analysis_tools.py on the mcp instance in server.py.

  from reaper_mcp.analysis_tools import register_tools as _reg_analysis
  
  _reg_project(mcp)
  _reg_track(mcp)
  _reg_midi(mcp)
  _reg_fx(mcp)
  _reg_audio(mcp)
  _reg_mixing(mcp)
  _reg_render(mcp)
  _reg_mastering(mcp)
  _reg_analysis(mcp)

• src/reaper_mcp/analysis_tools.py:21-21 (registration)

  The register_tools function that decorates analyze_transients (and analyze_frequency_spectrum) as MCP tools.

  def register_tools(mcp):

• src/reaper_mcp/render_tools.py:47-56 (helper)

  Helper function used by analyze_transients to render the project to a temporary WAV file for analysis.

  def render_to_temp_file(sample_rate: int = 48000) -> str:
      """
      Render the current project to a temporary WAV file and return its path.
      Used by analysis and mastering tools. Caller is responsible for deleting the file.
      """
      import tempfile
      tmp = tempfile.mktemp(suffix=".wav")
      _set_render_settings(tmp, "wav", sample_rate, 24, 2, bounds=0)
      RPR.Main_OnCommand(41824, 0)
      return tmp