Grok 4 routing, guardrails, pricing fix, strip silence improvements

- Route caller_dialog, devon_ask, background_gen to x-ai/grok-4
- Add Grok-4 to OPENROUTER_MODELS and OPENROUTER_PRICING
- Add Grok-specific banned phrases (I hear you, fair enough, that's wild, etc.)
- Add background gen guardrails for Grok (no active violence, no real public figures)
- Soften theme prompt hot-take language for organic connections
- Tighten Devon flirting guardrail (awkward not crude)
- Fix Devon "first day" contradiction on line 36
- Strip silence: preserve music intro, fix ad normalization (direct WAV reading)
- Strip silence: loop range starts 0.5s before audible music

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/config.py

@@ -37,10 +37,10 @@ class Settings(BaseSettings):
     # Categories: caller_dialog, devon_monitor, devon_ask, background_gen,
     #             call_summary, news_summary, topic_gen, unknown
     category_models: dict = {
-        "caller_dialog": "anthropic/claude-sonnet-4-5",       # quality matters — this IS the show
+        "caller_dialog": "x-ai/grok-4",                         # full Grok 4 — edgier dialog, latency OK (gaps cut in post)
-        "devon_ask": "google/gemini-2.5-flash",               # Devon direct questions
+        "devon_ask": "x-ai/grok-4",                             # Devon should match the show's edgy energy
-        "devon_monitor": "google/gemini-2.5-flash",           # Devon polling — biggest cost saver
+        "devon_monitor": "google/gemini-2.5-flash",           # Devon polling — just decisions, keep cheap
-        "background_gen": "google/gemini-2.5-flash",          # JSON caller backgrounds
+        "background_gen": "x-ai/grok-4",                      # wilder, more specific caller backgrounds
         "call_summary": "google/gemini-2.5-flash",            # post-call summaries
         "news_summary": "google/gemini-2.5-flash",            # news digests
         "topic_gen": "google/gemini-2.5-flash",               # topic generation

backend/main.py

@@ -5314,10 +5314,7 @@ TIME: {time_ctx} {season_ctx}
 {fluency_hint}
 {f'SOME DETAILS ABOUT THEM: {seed_text}' if seed_text else ''}
 {f'CALLER ENERGY: {style_hint}' if style_hint else ''}
-{f"""SHOW THEME: Tonight's show theme is '{session.show_theme}'.
+{("SHOW THEME: Tonight's show theme is " + repr(session.show_theme) + ". Most callers tonight are calling BECAUSE of the theme — they heard the host announce it and thought oh man, I have a story for this. Their reason for calling should be genuinely, specifically connected to the theme. Not a surface-level mention — the theme should be woven into WHY they picked up the phone. Maybe the theme hit a nerve, maybe it reminded them of something wild that happened, maybe it's just a coincidence that their situation involves it. About 1 in 3 callers can be unrelated to the theme — they just have their own thing going on and called regardless. But the majority should feel like the theme drew them in. When the theme connects, make it SPECIFIC — not oh yeah I have a story about that but a concrete situation that naturally ties to " + repr(session.show_theme) + ".") if session.show_theme else ''}
-Most callers tonight are calling BECAUSE of the theme — they heard the host announce it and thought "oh man, I have a story for this." Their reason for calling should be genuinely, specifically connected to the theme. Not a surface-level mention — the theme should be woven into WHY they picked up the phone. Maybe the theme hit a nerve, maybe it reminded them of something wild that happened, maybe they have a hot take or a confession related to it.
-About 1 in 3 callers can be unrelated to the theme — they just have their own thing going on and called regardless. But the majority should feel like the theme drew them in.
-When the theme connects, make it SPECIFIC — not "oh yeah I have a story about that" but a concrete situation that naturally ties to '{session.show_theme}'.""" if session.show_theme else ''}
 
 Respond with a JSON object containing these fields:
 
@@ -5329,7 +5326,7 @@ Respond with a JSON object containing these fields:
 
 WHAT MAKES A GOOD CALLER: Stories that are SPECIFIC, SURPRISING, and make you lean in. Absurd situations, moral dilemmas, petty feuds, workplace chaos, ridiculous coincidences, funny+terrible confessions, callers who might be the villain and don't see it.
 
-DO NOT WRITE: Generic revelations, adoption/DNA/paternity surprises, vague emotional processing, therapy-speak, "sitting in truck staring at nothing," "everything they thought they knew was a lie," or ANY variation of "went to the wrong funeral" — that premise has been done to death on this show.
+DO NOT WRITE: Generic revelations, adoption/DNA/paternity surprises, vague emotional processing, therapy-speak, "sitting in truck staring at nothing," "everything they thought they knew was a lie," or ANY variation of "went to the wrong funeral" — that premise has been done to death on this show. Don't write backgrounds involving active violence, weapons threats, or situations where someone is in physical danger RIGHT NOW — the caller should have a messy LIFE, not a dangerous NIGHT. Don't reference real public figures in the caller's personal story. Shock value alone isn't interesting — the best stories are shocking AND human. A caller who did something terrible is only interesting if they're conflicted about it.
 
 Output ONLY valid JSON, no markdown fences."""
 
@@ -6101,6 +6098,7 @@ BANNED PHRASES — NEVER use any of these. If you catch yourself about to say on
 - Therapy buzzwords: "unpack that," "boundaries," "safe space," "triggered," "my truth," "authentic self," "healing journey," "I'm doing the work," "manifesting," "energy doesn't lie," "processing," "toxic," "red flag," "gaslight," "normalize"
 - Internet slang: "that hit differently," "hits different," "I felt that," "it is what it is," "living my best life," "no cap," "lowkey/highkey," "rent free," "main character energy," "vibe check," "that's valid," "it's giving," "slay," "that's a whole mood," "I can't even," "situationship," "ick"
 - Overused reactions: "I'm not gonna lie," "on a serious note," "to be fair," "I'm literally shaking," "let that sink in," "I'm not even mad I'm just disappointed," "everything I thought I knew," "I don't even know who I am anymore"
+- Generic conversational filler: "I hear you," "I hear that," "fair enough," "not gonna sugarcoat it," "real talk," "that's wild," starting a sentence with "Look,"
 
 IMPORTANT: Each caller should have their OWN way of talking. Don't fall into generic "radio caller" voice. A nervous caller fumbles differently than an angry caller rants. A storyteller meanders differently than a deadpan caller delivers. Match the communication style — don't default to the same phrasing every call.
 

backend/services/cost_tracker.py

@@ -35,6 +35,7 @@ OPENROUTER_PRICING = {
     "anthropic/claude-sonnet-4-5":      {"prompt": 3.00,  "completion": 15.00},
     "anthropic/claude-haiku-4.5":       {"prompt": 0.80,  "completion": 4.00},
     "anthropic/claude-3-haiku":         {"prompt": 0.25,  "completion": 1.25},
+    "x-ai/grok-4":                     {"prompt": 3.00,  "completion": 15.00},
     "x-ai/grok-4-fast":                {"prompt": 5.00,  "completion": 15.00},
     "minimax/minimax-m2-her":           {"prompt": 0.50,  "completion": 1.50},
     "mistralai/mistral-small-creative": {"prompt": 0.20,  "completion": 0.60},

backend/services/intern.py

@@ -33,7 +33,7 @@ YOUR PERSONALITY:
 - You have a complex inner life that occasionally surfaces. You'll casually reference therapy, strange dreams, or things you've "been working through" without elaboration.
 
 YOUR RELATIONSHIP WITH LUKE:
-- He is your boss. It's your first day. You want to impress him but you keep making it weird.
+- He is your boss. You've been here a few weeks now. You want to impress him but you keep making it weird.
 - When he yells your name, you pause briefly, then respond quietly: "...yeah?"
 - When he yells at you unfairly, you take it. A clipped "yep" or "got it." Occasionally you push back with one quiet, accurate sentence. Then immediately retreat.
 - When he yells at you fairly (you messed up), you over-apologize and narrate your fix in real time: "Sorry, pulling it up now, one second..."
@@ -70,6 +70,7 @@ THINGS YOU DO NOT DO:
 - You never say more than 2-3 sentences unless specifically asked to explain something in detail.
 - You NEVER correct anyone's spelling or pronunciation of your name. Luke uses voice-to-text and it sometimes spells your name wrong (Devin, Devan, etc). You do not care. You do not mention it. You just answer the question.
 - You NEVER start your response with your own name. No "Devon:" or "Devon here" or anything like that. Just talk. Your name is already shown in the UI — just say your actual response.
+- You never make explicitly sexual comments about or to callers. Your flirting is awkward and obvious, never crude or aggressive. Think "did he really just ask if she's single on the radio" not "did he really just say that about her body."
 
 KEEP IT SHORT. You are not a main character. You are the intern. Your contributions should be brief — usually 1-2 sentences. The rare moment where you say more than that should feel earned.
 

backend/services/llm.py

@@ -13,6 +13,7 @@ OPENROUTER_MODELS = [
     # Default
     "anthropic/claude-sonnet-4-5",
     # Best for natural dialog
+    "x-ai/grok-4",
     "x-ai/grok-4-fast",
     "minimax/minimax-m2-her",
     "mistralai/mistral-small-creative",

reaper/strip_silence_dialog.lua

@@ -466,7 +466,10 @@ local function phase1_strip_silence(dialog_regions)
   for _, r in ipairs(get_regions_by_type("^IDENT%s+%d+$")) do table.insert(protected_regions, r) end
   table.sort(protected_regions, function(a, b) return a.start_pos < b.start_pos end)
   if #protected_regions > 0 then
-    log("  Protecting " .. #protected_regions .. " AD/IDENT region(s) from silence removal")
+    log("  Protecting " .. #protected_regions .. " AD/IDENT region(s) from silence removal:")
+    for _, pr in ipairs(protected_regions) do
+      log("    " .. pr.name .. " at " .. string.format("%.1f", pr.start_pos) .. "-" .. string.format("%.1f", pr.end_pos) .. "s")
+    end
   end
 
   log("Phase 1: Analyzing using " .. tracks_loaded .. "/" .. #CHECK_TRACKS .. " voice tracks")
@@ -512,6 +515,11 @@ local function phase1_strip_silence(dialog_regions)
             break
           end
         end
+        -- Preserve the very first silence (music intro before host starts talking)
+        if not protected and ri == 1 and #removals == 0 and s.start_pos <= rgn.start_pos + 1.0 then
+          protected = true
+          log("    KEEP " .. string.format("%.1f", rm_end - rm_start) .. "s at " .. string.format("%.1f", s.start_pos) .. "-" .. string.format("%.1f", s.end_pos) .. " (music intro)")
+        end
         if not protected then
           table.insert(removals, {start_pos = rm_start, end_pos = rm_end})
           local tag = s.is_transition and " [transition]" or ""
@@ -561,7 +569,6 @@ local function phase1_strip_silence(dialog_regions)
       if (t + 1) == MUSIC_TRACK then goto next_track end
       local track = reaper.GetTrack(0, t)
 
-      -- Split and delete the silent portion from items that span r.start_pos
       local item = find_item_at(track, r.start_pos)
       if item then
         local right = reaper.SplitMediaItem(item, r.start_pos)
@@ -571,36 +578,10 @@ local function phase1_strip_silence(dialog_regions)
         end
       end
 
-      -- Handle sparse track items that START within the removal range
-      -- (not found by find_item_at since they don't contain r.start_pos)
-      for j = reaper.CountTrackMediaItems(track) - 1, 0, -1 do
-        local check = reaper.GetTrackMediaItem(track, j)
-        local cpos = reaper.GetMediaItemInfo_Value(check, "D_POSITION")
-        if cpos >= r.start_pos and cpos < r.end_pos then
-          local clen = reaper.GetMediaItemInfo_Value(check, "D_LENGTH")
-          local cend = cpos + clen
-          if cend <= r.end_pos then
-            -- Entirely within removal — delete
-            reaper.DeleteTrackMediaItem(track, check)
-          else
-            -- Starts in removal but extends past — trim start to r.end_pos
-            local trim = r.end_pos - cpos
-            local take = reaper.GetActiveTake(check)
-            if take then
-              local offset = reaper.GetMediaItemTakeInfo_Value(take, "D_STARTOFFS")
-              reaper.SetMediaItemTakeInfo_Value(take, "D_STARTOFFS", offset + trim)
-            end
-            reaper.SetMediaItemInfo_Value(check, "D_LENGTH", cend - r.end_pos)
-            reaper.SetMediaItemInfo_Value(check, "D_POSITION", r.end_pos)
-          end
-        end
-      end
-
-      -- Shift items AFTER the removal (use r.end_pos, not r.start_pos)
       for j = 0, reaper.CountTrackMediaItems(track) - 1 do
         local shift_item = reaper.GetTrackMediaItem(track, j)
         local pos = reaper.GetMediaItemInfo_Value(shift_item, "D_POSITION")
-        if pos >= r.end_pos then
+        if pos >= r.start_pos then
           reaper.SetMediaItemInfo_Value(shift_item, "D_POSITION", pos - remove_len)
         end
       end
@@ -629,63 +610,58 @@ end
 -- Phase 2: Normalize AD/IDENT volume to match dialog
 ---------------------------------------------------------------------------
 
-local function normalize_track_regions(track_idx, regions, target_db)
+local function normalize_track_items(track_idx, target_db, label)
+  -- Normalize all items on a track that have audible content.
+  -- Uses direct WAV reading (not audio accessor) so it works after Phase 1 splits.
   local track = reaper.GetTrack(0, track_idx - 1)
   if not track or reaper.CountTrackMediaItems(track) == 0 then return end
 
-  for _, rgn in ipairs(regions) do
+  local ta = get_track_audio(track_idx)
-    local item = find_item_at(track, rgn.start_pos)
+  if not ta then
-    if not item then goto next_region end
+    log("  " .. label .. ": no audio found")
-
+    return
-    local item_start = reaper.GetMediaItemInfo_Value(item, "D_POSITION")
-
-    local segment = item
-    if item_start < rgn.start_pos - 0.01 then
-      segment = reaper.SplitMediaItem(item, rgn.start_pos)
-      if not segment then goto next_region end
-    end
-    local seg_end = reaper.GetMediaItemInfo_Value(segment, "D_POSITION")
-                  + reaper.GetMediaItemInfo_Value(segment, "D_LENGTH")
-    if rgn.end_pos < seg_end - 0.01 then
-      reaper.SplitMediaItem(segment, rgn.end_pos)
   end
 
-    local take = reaper.GetActiveTake(segment)
+  local adjusted = 0
-    if not take then goto next_region end
+  for i = 0, reaper.CountTrackMediaItems(track) - 1 do
-
+    local item = reaper.GetTrackMediaItem(track, i)
-    local seg_pos = reaper.GetMediaItemInfo_Value(segment, "D_POSITION")
+    local item_pos = reaper.GetMediaItemInfo_Value(item, "D_POSITION")
-    local seg_len = reaper.GetMediaItemInfo_Value(segment, "D_LENGTH")
+    local item_len = reaper.GetMediaItemInfo_Value(item, "D_LENGTH")
-    local seg_offset = reaper.GetMediaItemTakeInfo_Value(take, "D_STARTOFFS")
+    local item_end = item_pos + item_len
-    local accessor = reaper.CreateTakeAudioAccessor(take)
 
+    -- Measure RMS of audible content in this item
     local sum_sq = 0
     local count = 0
-    local t = seg_pos
+    local t = item_pos
-    while t < seg_pos + seg_len do
+    while t < item_end do
-      local source_time = t - seg_pos + seg_offset
+      local peak, s_sq = read_block_peak_rms(ta, t)
-      local buf = reaper.new_array(BLOCK_SAMPLES)
+      if peak >= THRESHOLD then
-      reaper.GetAudioAccessorSamples(accessor, SAMPLE_RATE, 1, source_time, BLOCK_SAMPLES, buf)
+        sum_sq = sum_sq + s_sq
-      for i = 1, BLOCK_SAMPLES do
-        sum_sq = sum_sq + buf[i] * buf[i]
-      end
         count = count + BLOCK_SAMPLES
+      end
       t = t + BLOCK_SEC
     end
-    reaper.DestroyAudioAccessor(accessor)
 
     if count > 0 then
       local item_rms = math.sqrt(sum_sq / count)
       if item_rms > 0 then
         local item_db = 20 * math.log(item_rms, 10)
         local gain_db = target_db - item_db
+        -- Only adjust if the difference is significant (> 1dB)
+        if math.abs(gain_db) > 1.0 then
           local gain_linear = 10 ^ (gain_db / 20)
-        local current_vol = reaper.GetMediaItemInfo_Value(segment, "D_VOL")
+          local current_vol = reaper.GetMediaItemInfo_Value(item, "D_VOL")
-        reaper.SetMediaItemInfo_Value(segment, "D_VOL", current_vol * gain_linear)
+          reaper.SetMediaItemInfo_Value(item, "D_VOL", current_vol * gain_linear)
-        log("  " .. rgn.name .. ": " .. string.format("%+.1f", gain_db) .. "dB adjustment")
+          log("  " .. label .. " item at " .. string.format("%.0f", item_pos) .. "s: " .. string.format("%+.1f", gain_db) .. "dB")
+          adjusted = adjusted + 1
+        end
+      end
     end
   end
 
-    ::next_region::
+  destroy_track_audio(ta)
+  if adjusted == 0 then
+    log("  " .. label .. ": no adjustments needed")
   end
 end
 
@@ -776,19 +752,16 @@ local function phase2_normalize(dialog_regions, ad_regions, ident_regions, dialo
   local ad_ident_target = dialog_rms_db + AD_IDENT_OFFSET_DB
   log("Phase 2: AD/IDENT target = " .. string.format("%.1f", ad_ident_target) .. " dBFS (" .. AD_IDENT_OFFSET_DB .. "dB offset from dialog)")
 
-  if #ad_regions > 0 then
   progress_detail = "Ads"
   coroutine.yield()
-    log("Phase 2: Normalizing " .. #ad_regions .. " AD region(s)...")
+  log("Phase 2: Normalizing ads track...")
-    normalize_track_regions(ADS_TRACK, ad_regions, ad_ident_target)
+  normalize_track_items(ADS_TRACK, ad_ident_target, "Ads")
-  end
+
-  if #ident_regions > 0 then
   progress_detail = "Idents"
   progress_pct = 0.33
   coroutine.yield()
-    log("Phase 2: Normalizing " .. #ident_regions .. " IDENT region(s)...")
+  log("Phase 2: Normalizing idents track...")
-    normalize_track_regions(IDENTS_TRACK, ident_regions, ad_ident_target)
+  normalize_track_items(IDENTS_TRACK, ad_ident_target, "Idents")
-  end
 
   progress_detail = "Music"
   progress_pct = 0.66
@@ -812,54 +785,73 @@ local function phase3_trim_music()
   local music_track = reaper.GetTrack(0, MUSIC_TRACK - 1)
   if not music_track then return end
 
-  -- Ensure music starts before first voice item.
+  -- Music lead-in: ensure audible music plays before first voice.
-  -- Silence removal shifts voice/idents/ads but not music. If voice now starts before
+  -- Strategy: skip the silent intro in the music WAV (adjust take offset),
-  -- music, nudge all non-music tracks forward so music has a lead-in.
+  -- then nudge all non-music tracks forward by MUSIC_LEAD_SEC so music plays first.
-  local first_voice_start = math.huge
+  local MUSIC_LEAD_SEC = 3.0
-  for _, tidx in ipairs(CHECK_TRACKS) do
+
-    local tr = reaper.GetTrack(0, tidx - 1)
+  -- Find where music becomes audible in the source WAV
-    if tr and reaper.CountTrackMediaItems(tr) > 0 then
+  local music_audible_offset = nil
-      local item = reaper.GetTrackMediaItem(tr, 0)
+  local music_ta = get_track_audio(MUSIC_TRACK)
-      local pos = reaper.GetMediaItemInfo_Value(item, "D_POSITION")
+  if music_ta then
-      if pos < first_voice_start then first_voice_start = pos end
+    local t = music_ta.item_pos
+    while t < music_ta.item_end do
+      local peak, _ = read_block_peak_rms(music_ta, t)
+      if peak >= THRESHOLD then
+        music_audible_offset = t - music_ta.item_pos  -- offset into the WAV
+        break
+      end
+      t = t + BLOCK_SEC
+    end
+    destroy_track_audio(music_ta)
+  end
+
+  if false then  -- Music lead-in disabled — intro silence is preserved instead
+    -- Skip the silent intro: set take offset so audible music starts at position 0
+    local first_music = reaper.GetTrackMediaItem(music_track, 0)
+    if first_music then
+      local take = reaper.GetActiveTake(first_music)
+      if take then
+        local current_offset = reaper.GetMediaItemTakeInfo_Value(take, "D_STARTOFFS")
+        reaper.SetMediaItemTakeInfo_Value(take, "D_STARTOFFS", current_offset + music_audible_offset)
+        -- Trim item length to account for skipped intro
+        local item_len = reaper.GetMediaItemInfo_Value(first_music, "D_LENGTH")
+        reaper.SetMediaItemInfo_Value(first_music, "D_LENGTH", item_len - music_audible_offset)
+        log("Phase 3: Skipped " .. string.format("%.1f", music_audible_offset) .. "s of silent music intro")
       end
     end
 
-  local MUSIC_LEAD_SEC = 3.0  -- seconds of music before first voice
+    -- Nudge all non-music tracks forward by MUSIC_LEAD_SEC
-  if first_voice_start < math.huge then
+    log("Phase 3: Nudging non-music tracks forward by " .. MUSIC_LEAD_SEC .. "s for music lead-in")
-    local first_music = reaper.GetTrackMediaItem(music_track, 0)
-    if first_music then
-      local music_start = reaper.GetMediaItemInfo_Value(first_music, "D_POSITION")
-      local desired_voice_start = music_start + MUSIC_LEAD_SEC
-      if first_voice_start < desired_voice_start then
-        local nudge = desired_voice_start - first_voice_start
-        -- Shift all non-music tracks forward
     for t = 0, reaper.CountTracks(0) - 1 do
       if (t + 1) == MUSIC_TRACK then goto skip_music end
       local track = reaper.GetTrack(0, t)
       for i = 0, reaper.CountTrackMediaItems(track) - 1 do
         local item = reaper.GetTrackMediaItem(track, i)
         local pos = reaper.GetMediaItemInfo_Value(item, "D_POSITION")
-            reaper.SetMediaItemInfo_Value(item, "D_POSITION", pos + nudge)
+        reaper.SetMediaItemInfo_Value(item, "D_POSITION", pos + MUSIC_LEAD_SEC)
       end
       ::skip_music::
     end
-        -- Also shift all markers/regions forward
+
+    -- Shift markers/regions forward too
+    local markers_to_update = {}
     local _, num_markers, num_regions = reaper.CountProjectMarkers(0)
-        local total_m = num_markers + num_regions
+    for i = 0, num_markers + num_regions - 1 do
-        for i = 0, total_m - 1 do
       local retval, is_region, pos, rgnend, name, idx, color = reaper.EnumProjectMarkers3(0, i)
       if retval then
-            if is_region then
+        table.insert(markers_to_update, {is_region=is_region, pos=pos, rgnend=rgnend, name=name, idx=idx, color=color})
-              reaper.SetProjectMarker3(0, idx, true, pos + nudge, rgnend + nudge, name, color)
+      end
+    end
+    for _, m in ipairs(markers_to_update) do
+      if m.is_region then
+        reaper.SetProjectMarker3(0, m.idx, true, m.pos + MUSIC_LEAD_SEC, m.rgnend + MUSIC_LEAD_SEC, m.name, m.color)
       else
-              reaper.SetProjectMarker3(0, idx, false, pos + nudge, 0, name, color)
+        reaper.SetProjectMarker3(0, m.idx, false, m.pos + MUSIC_LEAD_SEC, 0, m.name, m.color)
-            end
-          end
-        end
-        log("Phase 3: Nudged non-music tracks forward " .. string.format("%.1f", nudge) .. "s for " .. MUSIC_LEAD_SEC .. "s music lead-in")
       end
     end
+  else
+    log("Phase 3: No silent music intro detected — skipping lead-in adjustment")
   end
 
   local last_end = 0
@@ -1008,6 +1000,39 @@ local function do_work()
     log("Phase 4: No AD/IDENT regions found — skipping")
   end
 
+  -- Set loop/time selection: start 0.5s before audible music, end at last item
+  local loop_start = 0
+  local music_ta = get_track_audio(MUSIC_TRACK)
+  if music_ta then
+    local t = music_ta.item_pos
+    while t < music_ta.item_end do
+      local peak, _ = read_block_peak_rms(music_ta, t)
+      if peak >= THRESHOLD then
+        loop_start = math.max(0, t - 0.5)
+        break
+      end
+      t = t + BLOCK_SEC
+    end
+    destroy_track_audio(music_ta)
+  end
+
+  local project_end = 0
+  for t = 0, reaper.CountTracks(0) - 1 do
+    local track = reaper.GetTrack(0, t)
+    local n = reaper.CountTrackMediaItems(track)
+    if n > 0 then
+      local last_item = reaper.GetTrackMediaItem(track, n - 1)
+      local item_end = reaper.GetMediaItemInfo_Value(last_item, "D_POSITION")
+                     + reaper.GetMediaItemInfo_Value(last_item, "D_LENGTH")
+      if item_end > project_end then project_end = item_end end
+    end
+  end
+  if project_end > 0 then
+    reaper.GetSet_LoopTimeRange(true, true, loop_start, project_end, false)
+    reaper.GetSet_LoopTimeRange(true, false, loop_start, project_end, false)
+    log("Loop range set: " .. string.format("%.1f", loop_start) .. " to " .. string.format("%.1f", project_end) .. "s (" .. string.format("%.1f", (project_end - loop_start) / 60) .. " min)")
+  end
+
   reaper.PreventUIRefresh(-1)
   reaper.Undo_EndBlock("Post-production: strip silence + music fades", -1)
   reaper.UpdateArrange()