phase 2

core/api/detect/config.py

@@ -57,6 +57,13 @@ def write_config(update: ConfigUpdate):
     return _runtime_config
 
 
+@router.get("/config/profiles")
+def list_profiles():
+    """List available detection profiles."""
+    from detect.profiles import _PROFILES
+    return [{"name": name} for name in _PROFILES]
+
+
 @router.get("/config/stages", response_model=list[StageConfigInfo])
 def list_stage_configs():
     """Return the stage palette with config field metadata for the editor."""

core/api/detect/run.py

@@ -3,7 +3,11 @@ Pipeline run endpoints.
 
 POST /detect/run                — launch pipeline on selected source
 POST /detect/stop/{job_id}      — cancel a running pipeline
+POST /detect/pause/{job_id}     — pause after current stage
+POST /detect/resume/{job_id}    — resume a paused pipeline
+POST /detect/step/{job_id}      — run one stage then pause
 POST /detect/clear/{job_id}     — clear events from Redis
+GET  /detect/status/{job_id}    — pipeline run status
 """
 
 from __future__ import annotations
@@ -33,6 +37,7 @@ class RunRequest(BaseModel):
     skip_vlm: bool = False
     skip_cloud: bool = False
     log_level: str = "INFO"  # INFO | DEBUG
+    pause_after_stage: bool = False
 
 
 class RunResponse(BaseModel):
@@ -92,9 +97,13 @@ def run_pipeline(req: RunRequest):
         source_asset_id=req.source_asset_id,
     )
 
-    from detect.graph import PipelineCancelled, set_cancel_check, clear_cancel_check
+    from detect.graph import (
+        PipelineCancelled, set_cancel_check, clear_cancel_check,
+        init_pause, clear_pause,
+    )
 
     set_cancel_check(job_id, lambda: job_id in _cancelled_jobs)
+    init_pause(job_id, pause_after_stage=req.pause_after_stage)
 
     def _run():
         try:
@@ -123,6 +132,7 @@ def run_pipeline(req: RunRequest):
             _running_jobs.pop(job_id, None)
             _cancelled_jobs.discard(job_id)
             clear_cancel_check(job_id)
+            clear_pause(job_id)
             emit.clear_run_context()
 
     thread = threading.Thread(target=_run, daemon=True, name=f"pipeline-{job_id}")
@@ -145,6 +155,75 @@ def stop_pipeline(job_id: str):
     return {"status": "stopping", "job_id": job_id}
 
 
+@router.post("/pause/{job_id}")
+def pause(job_id: str):
+    """Pause a running pipeline after the current stage completes."""
+    from detect.graph import pause_pipeline
+
+    if job_id not in _running_jobs:
+        raise HTTPException(status_code=404, detail=f"No running pipeline: {job_id}")
+
+    pause_pipeline(job_id)
+    return {"status": "pausing", "job_id": job_id}
+
+
+@router.post("/resume/{job_id}")
+def resume(job_id: str):
+    """Resume a paused pipeline."""
+    from detect.graph import resume_pipeline
+
+    if job_id not in _running_jobs:
+        raise HTTPException(status_code=404, detail=f"No running pipeline: {job_id}")
+
+    resume_pipeline(job_id)
+    return {"status": "running", "job_id": job_id}
+
+
+@router.post("/step/{job_id}")
+def step(job_id: str):
+    """Run one stage then pause again."""
+    from detect.graph import step_pipeline
+
+    if job_id not in _running_jobs:
+        raise HTTPException(status_code=404, detail=f"No running pipeline: {job_id}")
+
+    step_pipeline(job_id)
+    return {"status": "stepping", "job_id": job_id}
+
+
+@router.post("/pause-after-stage/{job_id}")
+def toggle_pause_after_stage(job_id: str, enabled: bool = True):
+    """Toggle pause-after-each-stage mode."""
+    from detect.graph import set_pause_after_stage
+
+    if job_id not in _running_jobs:
+        raise HTTPException(status_code=404, detail=f"No running pipeline: {job_id}")
+
+    set_pause_after_stage(job_id, enabled)
+    return {"status": "ok", "pause_after_stage": enabled, "job_id": job_id}
+
+
+@router.get("/status/{job_id}")
+def pipeline_status(job_id: str):
+    """Get pipeline run status."""
+    from detect.graph import is_paused
+
+    running = job_id in _running_jobs
+    paused = is_paused(job_id)
+    cancelling = job_id in _cancelled_jobs
+
+    if cancelling:
+        status = "cancelling"
+    elif paused:
+        status = "paused"
+    elif running:
+        status = "running"
+    else:
+        status = "idle"
+
+    return {"status": status, "job_id": job_id}
+
+
 @router.post("/clear/{job_id}")
 def clear_pipeline(job_id: str):
     """Clear events for a job from Redis."""

detect/graph/__init__.py

@@ -4,7 +4,7 @@ Detection pipeline graph.
     detect/graph/
         nodes.py    — node functions (one per stage)
         events.py   — graph_update SSE emission
-        runner.py   — pipeline execution (LangGraph wrapper, checkpoint, cancel)
+        runner.py   — pipeline execution (LangGraph wrapper, checkpoint, cancel, pause)
 """
 
 from .nodes import NODES, NODE_FUNCTIONS
@@ -12,8 +12,15 @@ from .runner import (
     PipelineCancelled,
     build_graph,
     clear_cancel_check,
+    clear_pause,
     get_pipeline,
+    init_pause,
+    is_paused,
+    pause_pipeline,
+    resume_pipeline,
     set_cancel_check,
+    set_pause_after_stage,
+    step_pipeline,
 )
 from .events import _node_states
 
@@ -25,5 +32,12 @@ __all__ = [
     "get_pipeline",
     "set_cancel_check",
     "clear_cancel_check",
+    "init_pause",
+    "clear_pause",
+    "pause_pipeline",
+    "resume_pipeline",
+    "step_pipeline",
+    "set_pause_after_stage",
+    "is_paused",
     "_node_states",
 ]

detect/graph/runner.py

@@ -7,13 +7,17 @@ custom runner in Phase 3, with an executor socket for distributed dispatch.
 
 from __future__ import annotations
 
+import logging
 import os
+import threading
 
 from langgraph.graph import END, StateGraph
 
 from detect.state import DetectState
 from .nodes import NODES, NODE_FUNCTIONS
 
+logger = logging.getLogger(__name__)
+
 
 # --- Checkpoint wrapper ---
 
@@ -27,7 +31,15 @@ class PipelineCancelled(Exception):
     pass
 
 
-# Cancellation hook — set by the run endpoint, checked before each node
+class PipelinePaused(Exception):
+    """Raised when a pipeline is paused (internally, for flow control)."""
+    pass
+
+
+# ---------------------------------------------------------------------------
+# Cancellation — checked before each node
+# ---------------------------------------------------------------------------
+
 _cancel_check: dict[str, callable] = {}
 
 
@@ -39,6 +51,92 @@ def clear_cancel_check(job_id: str):
     _cancel_check.pop(job_id, None)
 
 
+# ---------------------------------------------------------------------------
+# Pause / Resume / Step — checked after each node completes
+#
+# _pause_gate: threading.Event per job. When cleared, the runner blocks.
+#              When set, the runner proceeds to the next node.
+# _pause_after_stage: if True, automatically clear the gate after each node.
+# ---------------------------------------------------------------------------
+
+_pause_gate: dict[str, threading.Event] = {}
+_pause_after_stage: dict[str, bool] = {}
+
+
+def init_pause(job_id: str, pause_after_stage: bool = False):
+    """Initialize pause state for a job. Called when pipeline starts."""
+    gate = threading.Event()
+    gate.set()  # start unpaused
+    _pause_gate[job_id] = gate
+    _pause_after_stage[job_id] = pause_after_stage
+
+
+def clear_pause(job_id: str):
+    """Clean up pause state. Called when pipeline finishes."""
+    _pause_gate.pop(job_id, None)
+    _pause_after_stage.pop(job_id, None)
+
+
+def pause_pipeline(job_id: str):
+    """Pause a running pipeline. It will block after the current stage completes."""
+    gate = _pause_gate.get(job_id)
+    if gate:
+        gate.clear()
+        logger.info("Pipeline %s paused", job_id)
+
+
+def resume_pipeline(job_id: str):
+    """Resume a paused pipeline."""
+    gate = _pause_gate.get(job_id)
+    if gate:
+        gate.set()
+        logger.info("Pipeline %s resumed", job_id)
+
+
+def step_pipeline(job_id: str):
+    """Run one stage then pause again."""
+    _pause_after_stage[job_id] = True
+    gate = _pause_gate.get(job_id)
+    if gate:
+        gate.set()  # unblock for one stage, _pause_after_stage re-pauses after
+        logger.info("Pipeline %s stepping", job_id)
+
+
+def set_pause_after_stage(job_id: str, enabled: bool):
+    """Toggle pause-after-each-stage mode."""
+    _pause_after_stage[job_id] = enabled
+    if not enabled:
+        # If disabling, also resume in case we're currently paused
+        gate = _pause_gate.get(job_id)
+        if gate:
+            gate.set()
+
+
+def is_paused(job_id: str) -> bool:
+    """Check if a pipeline is currently paused."""
+    gate = _pause_gate.get(job_id)
+    return gate is not None and not gate.is_set()
+
+
+def _wait_if_paused(job_id: str, node_name: str):
+    """Block until resumed. Called after each node completes."""
+    gate = _pause_gate.get(job_id)
+    if gate is None:
+        return
+
+    # If pause-after-stage is on, pause now
+    if _pause_after_stage.get(job_id, False):
+        gate.clear()
+        from detect import emit
+        emit.log(job_id, "Pipeline", "INFO", f"Paused after {node_name}")
+
+    # Block until gate is set (resume/step) or cancelled
+    while not gate.wait(timeout=0.5):
+        check = _cancel_check.get(job_id)
+        if check and check():
+            raise PipelineCancelled(f"Cancelled while paused before next stage")
+
+
 def _checkpointing_node(node_name: str, node_fn):
     """Wrap a node function to auto-checkpoint after completion."""
 
@@ -81,6 +179,10 @@ def _checkpointing_node(node_name: str, node_fn):
             output_json=output_json,
         )
         _latest_checkpoint[job_id] = new_checkpoint_id
+
+        # Pause check — blocks if paused, respects cancel while waiting
+        _wait_if_paused(job_id, node_name)
+
         return result
 
     wrapper.__name__ = node_fn.__name__

ui/detection-app/src/App.vue

@@ -24,8 +24,10 @@ const logPanel = ref<{ clear: () => void } | null>(null)
 
 // SSE connection + pipeline status
 const {
-  jobId, stats, runContext, status, sseConnected, source,
+  jobId, stats, runContext, status, paused, pauseAfterStage,
-  stopPipeline, onJobStarted: sseJobStarted,
+  sseConnected, source,
+  stopPipeline, pausePipeline, resumePipeline, stepPipeline,
+  togglePauseAfterStage, onJobStarted: sseJobStarted,
 } = useSSEConnection()
 
 // Checkpoint frames + navigation
@@ -50,9 +52,9 @@ function setCheckpointFrame(index: number) {
 }
 
 // Wire job start to clear log panel
-function onJobStarted(newJobId: string) {
+function onJobStarted(newJobId: string, opts?: { pauseAfterStage?: boolean }) {
   logPanel.value?.clear()
-  sseJobStarted(newJobId)
+  sseJobStarted(newJobId, opts)
 }
 
 </script>
@@ -62,20 +64,52 @@ function onJobStarted(newJobId: string) {
     <header>
       <h1>Detection Pipeline</h1>
       <span class="status-badge" :class="status">{{ status }}</span>
-      <span v-if="runContext" class="run-info">
-        {{ runContext.run_type }} · run: {{ runContext.run_id }}
-      </span>
       <button class="header-btn" title="Select source" @click="pipeline.openSourceSelector()">
         <svg width="14" height="14" viewBox="0 0 16 16" fill="none" stroke="currentColor" stroke-width="1.5">
           <path d="M2 4h4l2 2h6v8H2V4z"/><path d="M2 4V2h12v2"/>
         </svg>
       </button>
+
+      <!-- Transport controls — visible when a pipeline is running -->
+      <div v-if="sseConnected && (status === 'live' || status === 'processing' || paused)" class="transport">
+        <button
+          v-if="paused"
+          class="header-btn play-btn"
+          title="Resume"
+          @click="resumePipeline"
+        >
+          <svg width="12" height="12" viewBox="0 0 12 12" fill="currentColor"><polygon points="2,1 11,6 2,11"/></svg>
+        </button>
+        <button
+          v-else
+          class="header-btn pause-btn"
+          title="Pause after current stage"
+          @click="pausePipeline"
+        >
+          <svg width="12" height="12" viewBox="0 0 12 12" fill="currentColor"><rect x="2" y="1" width="3" height="10"/><rect x="7" y="1" width="3" height="10"/></svg>
+        </button>
+        <button
+          class="header-btn step-btn"
+          title="Run one stage"
+          @click="stepPipeline"
+          :disabled="!paused"
+        >
+          <svg width="12" height="12" viewBox="0 0 12 12" fill="currentColor"><polygon points="1,1 7,6 1,11"/><rect x="8" y="1" width="2.5" height="10"/></svg>
+        </button>
         <button
-        v-if="sseConnected && (status === 'live' || status === 'processing')"
           class="header-btn stop-btn"
           title="Stop pipeline"
           @click="stopPipeline"
-      >■</button>
+        >
+          <svg width="10" height="10" viewBox="0 0 10 10" fill="currentColor"><rect width="10" height="10"/></svg>
+        </button>
+        <label class="pause-toggle" title="Pause after each stage">
+          <input type="checkbox" :checked="pauseAfterStage" @change="togglePauseAfterStage" />
+          <span>step</span>
+        </label>
+      </div>
+
+      <span v-if="paused" class="status-badge paused">PAUSED</span>
       <span class="job-id">job: {{ jobId || '—' }}</span>
     </header>
 
@@ -203,19 +237,14 @@ function onJobStarted(newJobId: string) {
         </Panel>
 
         <!-- === SOURCE SELECTOR MODE === -->
-        <SourceSelector v-else-if="pipeline.layoutMode === 'source_selector'" @job-started="onJobStarted" />
+        <SourceSelector v-else-if="pipeline.layoutMode === 'source_selector'" @job-started="(id: string, opts: any) => onJobStarted(id, opts)" />
 
       </template>
     </SplitPane>
 
-    <!-- Bottom bar: Log or Blob viewer depending on mode -->
+    <!-- Bottom bar: Log (hidden in source selector) -->
-    <div class="log-row">
+    <div v-if="pipeline.layoutMode !== 'source_selector'" class="log-row">
-      <template v-if="pipeline.layoutMode === 'source_selector'">
-        <!-- no log in source selector -->
-      </template>
-      <template v-else>
       <LogPanel ref="logPanel" :source="source" :status="status" />
-      </template>
     </div>
   </div>
 </template>
@@ -283,6 +312,16 @@ header h1 { font-size: var(--font-size-lg); font-weight: 600; }
   background: var(--surface-3);
   color: var(--text-primary);
 }
+.transport {
+  display: flex;
+  align-items: center;
+  gap: 2px;
+}
+
+.play-btn { color: var(--status-live); }
+.pause-btn { color: var(--text-secondary); }
+.step-btn { color: var(--text-secondary); }
+.step-btn:disabled { opacity: 0.3; cursor: not-allowed; }
 .stop-btn {
   background: var(--status-error);
   color: #000;
@@ -293,6 +332,19 @@ header h1 { font-size: var(--font-size-lg); font-weight: 600; }
   opacity: 0.8;
 }
 
+.pause-toggle {
+  display: flex;
+  align-items: center;
+  gap: 4px;
+  font-size: 10px;
+  color: var(--text-dim);
+  cursor: pointer;
+  margin-left: 4px;
+}
+.pause-toggle input { accent-color: var(--status-processing); }
+
+.status-badge.paused { background: var(--status-processing); color: #000; }
+
 .job-id { color: var(--text-dim); font-size: var(--font-size-sm); margin-left: auto; }
 
 .stats-col {

ui/detection-app/src/composables/useSSEConnection.ts

@@ -68,6 +68,9 @@ export function useSSEConnection() {
     sseConnected.value = true
   }
 
+  const paused = ref(false)
+  const pauseAfterStage = ref(false)
+
   async function stopPipeline() {
     if (!jobId.value) return
     try {
@@ -75,11 +78,70 @@ export function useSSEConnection() {
     } catch { /* ignore — UI will see the cancel event via SSE */ }
   }
 
-  function onJobStarted(newJobId: string) {
+  async function pausePipeline() {
+    if (!jobId.value) return
+    try {
+      await fetch(`/api/detect/pause/${jobId.value}`, { method: 'POST' })
+      paused.value = true
+    } catch { /* ignore */ }
+  }
+
+  async function resumePipeline() {
+    if (!jobId.value) return
+    try {
+      await fetch(`/api/detect/resume/${jobId.value}`, { method: 'POST' })
+      paused.value = false
+    } catch { /* ignore */ }
+  }
+
+  async function stepPipeline() {
+    if (!jobId.value) return
+    try {
+      await fetch(`/api/detect/step/${jobId.value}`, { method: 'POST' })
+      paused.value = false  // briefly unpaused, will re-pause after stage
+    } catch { /* ignore */ }
+  }
+
+  async function togglePauseAfterStage() {
+    if (!jobId.value) return
+    const next = !pauseAfterStage.value
+    try {
+      await fetch(`/api/detect/pause-after-stage/${jobId.value}?enabled=${next}`, { method: 'POST' })
+      pauseAfterStage.value = next
+    } catch { /* ignore */ }
+  }
+
+  // Poll pipeline status to track paused state
+  // (SSE doesn't emit pause events — the thread is blocked)
+  let statusPoll: ReturnType<typeof setInterval> | null = null
+
+  function startStatusPoll() {
+    if (statusPoll) return
+    statusPoll = setInterval(async () => {
+      if (!jobId.value) return
+      try {
+        const resp = await fetch(`/api/detect/status/${jobId.value}`)
+        if (!resp.ok) return
+        const data = await resp.json()
+        paused.value = data.status === 'paused'
+      } catch { /* ignore */ }
+    }, 1000)
+  }
+
+  function stopStatusPoll() {
+    if (statusPoll) {
+      clearInterval(statusPoll)
+      statusPoll = null
+    }
+  }
+
+  function onJobStarted(newJobId: string, opts?: { pauseAfterStage?: boolean }) {
     jobId.value = newJobId
     stats.value = null
     runContext.value = null
     status.value = 'processing'
+    paused.value = false
+    pauseAfterStage.value = opts?.pauseAfterStage ?? false
     pipeline.reset()
     pipeline.setStatus('running')
     // Update URL without reload
@@ -91,16 +153,34 @@ export function useSSEConnection() {
     source.setUrl(`/api/detect/stream/${newJobId}`)
     source.connect()
     sseConnected.value = true
+    startStatusPoll()
   }
 
+  // Start polling if we already have an active job
+  if (jobId.value && sseConnected.value) {
+    startStatusPoll()
+  }
+
+  // Stop polling when job completes
+  source.on<{ report?: { status?: string } }>('job_complete', () => {
+    stopStatusPoll()
+    paused.value = false
+  })
+
   return {
     jobId,
     stats,
     runContext,
     status,
+    paused,
+    pauseAfterStage,
     sseConnected,
     source: source as DataSource,
     stopPipeline,
+    pausePipeline,
+    resumePipeline,
+    stepPipeline,
+    togglePauseAfterStage,
     onJobStarted,
   }
 }

ui/detection-app/src/panels/PipelineGraphPanel.vue

@@ -17,6 +17,7 @@ const nodes = ref<GraphNode[]>([])
 
 // Derive graph mode from pipeline layout mode
 const graphMode = computed<GraphMode>(() => {
+  if (pipeline.layoutMode === 'source_selector') return 'observe'
   if (pipeline.layoutMode === 'bbox_editor') return 'edit-isolated'
   if (pipeline.layoutMode === 'stage_editor') return 'edit-in-pipeline'
   return 'observe'
@@ -29,6 +30,20 @@ watch(stageNames, (names) => {
   }
 }, { immediate: true })
 
+// Source selector: placeholders until a chunk is selected, then real stage names
+const displayNodes = computed<GraphNode[]>(() => {
+  if (pipeline.layoutMode === 'source_selector') {
+    if (pipeline.sourceHasSelection) {
+      return stageNames.value.map((id) => ({ id, status: 'pending' as const }))
+    }
+    return Array.from({ length: 10 }, (_, i) => ({
+      id: `_placeholder_${i}`,
+      status: 'placeholder' as const,
+    }))
+  }
+  return nodes.value
+})
+
 props.source.on<{ nodes: GraphNode[] }>('graph_update', (e) => {
   nodes.value = e.nodes
 })
@@ -60,7 +75,7 @@ function onOpenStageEditor(stage: string) {
 <template>
   <Panel title="Pipeline" :status="status">
     <GraphRenderer
-      :nodes="nodes"
+      :nodes="displayNodes"
       :mode="graphMode"
       :active-stage="pipeline.editorStage"
       :region-stages="editableStages"

ui/detection-app/src/panels/SourceSelector.vue

@@ -25,15 +25,22 @@ const SOURCE_TYPE_LABELS: Record<string, string> = {
   stream:    'STREAM',
 }
 
+interface ProfileInfo {
+  name: string
+}
+
 const sources = ref<SourceInfo[]>([])
 const chunks = ref<ChunkInfo[]>([])
+const profiles = ref<ProfileInfo[]>([])
 const selectedSource = ref<string | null>(null)
-const selectedChunk = ref<string | null>(null)
+const selectedChunks = ref<Set<string>>(new Set())
+const selectedProfile = ref('soccer_broadcast')
 const loading = ref(false)
 const running = ref(false)
 const skipVlm = ref(false)
 const skipCloud = ref(true)
 const checkpoint = ref(true)
+const pauseAfterStage = ref(false)
 const logLevel = ref('INFO')
 const error = ref<string | null>(null)
 
@@ -41,9 +48,19 @@ async function loadSources() {
   loading.value = true
   error.value = null
   try {
-    const resp = await fetch('/api/detect/sources')
+    const [srcResp, profResp] = await Promise.all([
-    if (!resp.ok) throw new Error(`${resp.status} ${resp.statusText}`)
+      fetch('/api/detect/sources'),
-    sources.value = await resp.json()
+      fetch('/api/detect/config/profiles'),
+    ])
+    if (!srcResp.ok) throw new Error(`${srcResp.status} ${srcResp.statusText}`)
+    sources.value = await srcResp.json()
+
+    if (profResp.ok) {
+      profiles.value = await profResp.json()
+      if (profiles.value.length > 0 && !profiles.value.find(p => p.name === selectedProfile.value)) {
+        selectedProfile.value = profiles.value[0].name
+      }
+    }
   } catch (e: any) {
     error.value = `Failed to load sources: ${e.message}`
   } finally {
@@ -53,7 +70,7 @@ async function loadSources() {
 
 async function loadChunks(jobId: string) {
   selectedSource.value = jobId
-  selectedChunk.value = null
+  selectedChunks.value = new Set()
   chunks.value = []
   try {
     const resp = await fetch(`/api/detect/sources/${jobId}/chunks`)
@@ -64,8 +81,25 @@ async function loadChunks(jobId: string) {
   }
 }
 
-function selectChunk(chunk: ChunkInfo) {
+function toggleChunk(chunk: ChunkInfo) {
-  selectedChunk.value = chunk.key
+  const s = new Set(selectedChunks.value)
+  if (s.has(chunk.key)) {
+    s.delete(chunk.key)
+  } else {
+    s.add(chunk.key)
+  }
+  selectedChunks.value = s
+  pipeline.sourceHasSelection = s.size > 0
+}
+
+function selectAllChunks() {
+  selectedChunks.value = new Set(chunks.value.map(c => c.key))
+  pipeline.sourceHasSelection = true
+}
+
+function clearSelection() {
+  selectedChunks.value = new Set()
+  pipeline.sourceHasSelection = false
 }
 
 async function openPreview(chunk: ChunkInfo) {
@@ -83,24 +117,29 @@ async function openPreview(chunk: ChunkInfo) {
 }
 
 const emit = defineEmits<{
-  (e: 'job-started', jobId: string): void
+  (e: 'job-started', jobId: string, opts: { pauseAfterStage: boolean }): void
 }>()
 
 async function runPipeline() {
-  if (!selectedChunk.value) return
+  if (selectedChunks.value.size === 0) return
   running.value = true
   error.value = null
 
+  // Run first selected chunk (multi-run queuing is future work)
+  const videoPath = [...selectedChunks.value][0]
+
   try {
     const resp = await fetch('/api/detect/run', {
       method: 'POST',
       headers: { 'Content-Type': 'application/json' },
       body: JSON.stringify({
-        video_path: selectedChunk.value,
+        video_path: videoPath,
+        profile_name: selectedProfile.value,
         checkpoint: checkpoint.value,
         skip_vlm: skipVlm.value,
         skip_cloud: skipCloud.value,
         log_level: logLevel.value,
+        pause_after_stage: pauseAfterStage.value,
       }),
     })
     if (!resp.ok) {
@@ -109,7 +148,7 @@ async function runPipeline() {
     }
 
     const data = await resp.json()
-    emit('job-started', data.job_id)
+    emit('job-started', data.job_id, { pauseAfterStage: pauseAfterStage.value })
   } catch (e: any) {
     error.value = `Failed to start pipeline: ${e.message}`
     running.value = false
@@ -160,13 +199,20 @@ onMounted(loadSources)
 
       <!-- Chunk list -->
       <div class="source-section" v-if="chunks.length > 0">
+        <div class="chunk-header">
           <h3>Chunks</h3>
+          <span class="chunk-actions">
+            <button class="link-btn" @click="selectAllChunks">all</button>
+            <button class="link-btn" @click="clearSelection">none</button>
+            <span v-if="selectedChunks.size > 0" class="selection-count">{{ selectedChunks.size }} selected</span>
+          </span>
+        </div>
         <div class="chunk-list">
           <div
             v-for="chunk in chunks"
             :key="chunk.key"
-            :class="['chunk-item', { selected: selectedChunk === chunk.key }]"
+            :class="['chunk-item', { selected: selectedChunks.has(chunk.key) }]"
-            @click="selectChunk(chunk)"
+            @click="toggleChunk(chunk)"
           >
             <span class="chunk-name">{{ chunk.filename }}</span>
             <span class="chunk-meta">
@@ -182,11 +228,18 @@ onMounted(loadSources)
       </div>
 
       <!-- Run options -->
-      <div class="run-options" v-if="selectedChunk">
+      <div class="run-options" v-if="selectedChunks.size > 0">
         <h3>Run Options</h3>
+        <label>
+          Profile
+          <select v-model="selectedProfile" class="log-level-select">
+            <option v-for="p in profiles" :key="p.name" :value="p.name">{{ p.name.replace(/_/g, ' ') }}</option>
+          </select>
+        </label>
         <label><input type="checkbox" v-model="checkpoint"> Checkpointing</label>
         <label><input type="checkbox" v-model="skipVlm"> Skip VLM</label>
         <label><input type="checkbox" v-model="skipCloud"> Skip Cloud</label>
+        <label><input type="checkbox" v-model="pauseAfterStage"> Pause after each stage</label>
         <label>
           Log level
           <select v-model="logLevel" class="log-level-select">
@@ -195,10 +248,10 @@ onMounted(loadSources)
           </select>
         </label>
 
-        <div class="selected-path">{{ selectedChunk }}</div>
+        <div class="selected-path">{{ [...selectedChunks].join(', ') }}</div>
 
         <button class="run-btn" @click="runPipeline" :disabled="running">
-          {{ running ? 'Starting...' : 'Run Pipeline' }}
+          {{ running ? 'Starting...' : selectedChunks.size === 1 ? 'Run Pipeline' : `Run Pipeline (${selectedChunks.size} chunks)` }}
         </button>
       </div>
 
@@ -239,6 +292,35 @@ onMounted(loadSources)
   letter-spacing: 0.05em;
 }
 
+.chunk-header {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+}
+
+.chunk-actions {
+  display: flex;
+  align-items: center;
+  gap: var(--space-2);
+}
+
+.link-btn {
+  background: none;
+  border: none;
+  color: var(--text-dim);
+  font-family: var(--font-mono);
+  font-size: 10px;
+  cursor: pointer;
+  text-decoration: underline;
+  padding: 0;
+}
+.link-btn:hover { color: var(--text-primary); }
+
+.selection-count {
+  font-size: 10px;
+  color: var(--text-secondary);
+}
+
 .source-list, .chunk-list {
   max-height: 200px;
   overflow-y: auto;

ui/detection-app/src/stores/pipeline.ts

@@ -24,6 +24,8 @@ export const usePipelineStore = defineStore('pipeline', () => {
   const layoutMode = ref<string>('normal')
   const editorStage = ref<string | null>(null)
 
+  const sourceHasSelection = ref(false)
+
   const isRunning = computed(() => status.value === 'running')
   const isPaused = computed(() => status.value === 'paused')
   const canReplay = computed(() => checkpoints.value.length > 0)
@@ -76,12 +78,14 @@ export const usePipelineStore = defineStore('pipeline', () => {
   function closeEditor() {
     layoutMode.value = 'normal'
     editorStage.value = null
+    sourceHasSelection.value = false
   }
 
   function reset() {
     status.value = 'idle'
     layoutMode.value = 'normal'
     editorStage.value = null
+    sourceHasSelection.value = false
     nodes.value = []
     currentStage.value = null
     runId.value = null
@@ -92,7 +96,7 @@ export const usePipelineStore = defineStore('pipeline', () => {
 
   return {
     jobId, status, nodes, currentStage, runId, parentJobId, runType,
-    checkpoints, error, layoutMode, editorStage,
+    checkpoints, error, layoutMode, editorStage, sourceHasSelection,
     isRunning, isPaused, canReplay, isEditing,
     setJob, setStatus, updateNodes, setRunContext, setCheckpoints, setError,
     openSourceSelector, openBBoxEditor, openStageEditor, closeEditor, reset,

ui/framework/src/renderers/GraphRenderer.vue

@@ -6,7 +6,7 @@ import '@vue-flow/core/dist/theme-default.css'
 
 export interface GraphNode {
   id: string
-  status: 'pending' | 'running' | 'done' | 'error' | 'skipped'
+  status: 'pending' | 'running' | 'done' | 'error' | 'skipped' | 'placeholder'
   /** Whether a checkpoint exists at this stage */
   hasCheckpoint?: boolean
   /** Stage category (e.g. 'cv', 'ai', 'preprocessing') */
@@ -44,6 +44,7 @@ const STATUS_COLORS: Record<string, string> = {
   done: 'var(--status-live)',
   error: 'var(--status-error)',
   skipped: '#4a6fa5',
+  placeholder: 'transparent',
 }
 
 function nodeAppearance(node: GraphNode) {
@@ -84,6 +85,16 @@ function nodeAppearance(node: GraphNode) {
     }
   }
 
+  // Placeholder: hollow, no text
+  if (node.status === 'placeholder') {
+    return {
+      color: 'transparent',
+      textColor: 'transparent',
+      opacity: 0.6,
+      outline: false,
+    }
+  }
+
   // Default: observe mode or downstream in edit-in-pipeline
   return {
     color: STATUS_COLORS[node.status] ?? STATUS_COLORS.pending,
@@ -158,6 +169,7 @@ function onNodeClick(id: string) {
             active: data.isActive,
             outline: data.outline,
             dimmed: data.opacity < 1,
+            placeholder: data.status === 'placeholder',
           }"
           :style="{
             background: data.color,
@@ -248,6 +260,18 @@ function onNodeClick(id: string) {
   pointer-events: none;
 }
 
+.stage-node.placeholder {
+  border: 1px dashed var(--text-secondary);
+  background: transparent;
+  color: transparent;
+  pointer-events: none;
+}
+
+.stage-node.placeholder .stage-actions,
+.stage-node.placeholder .checkpoint-badge {
+  display: none;
+}
+
 .stage-label {
   flex: 1;
 }