diff --git a/docker-compose.dev.yml b/docker-compose.dev.yml
new file mode 100644
index 0000000..39edd32
--- /dev/null
+++ b/docker-compose.dev.yml
@@ -0,0 +1,54 @@
+# Developer-focused Docker Compose for local development
+# Simplified from deployments/docker-compose.dev.yml for quick local dev
+
+services:
+  redis:
+    image: redis:7-alpine
+    ports:
+      - "6379:6379"
+    volumes:
+      - redis_data:/data
+    command: redis-server --appendonly yes
+
+  api-server:
+    build:
+      context: .
+      dockerfile: build/docker/simple.Dockerfile
+    ports:
+      - "9101:9101"
+    volumes:
+      - .:/workspace
+      - ./data/dev/logs:/logs
+      - ./data/dev/experiments:/data/experiments
+      - ./data/dev/active:/data/active
+    environment:
+      - LOG_LEVEL=debug
+      - LOG_FORMAT=text
+      - ENV=development
+    depends_on:
+      - redis
+    command: ["/bin/sh", "-c", "mkdir -p /data/experiments /data/active && exec /usr/local/bin/api-server -config /app/configs/api/dev.yaml"]
+
+  worker:
+    build:
+      context: .
+      dockerfile: build/docker/simple.Dockerfile
+    ports:
+      - "9102:9102"
+    volumes:
+      - .:/workspace
+      - ./data/dev/logs:/logs
+      - ./data/dev/active:/data/active
+      - ./data/dev/experiments:/data/experiments
+      - /var/run/docker.sock:/var/run/docker.sock
+    environment:
+      - LOG_LEVEL=debug
+      - LOG_FORMAT=text
+      - ENV=development
+    depends_on:
+      - redis
+      - api-server
+    command: ["/usr/local/bin/worker", "-config", "/app/configs/worker.yaml"]
+
+volumes:
+  redis_data:
diff --git a/internal/manifest/validator.go b/internal/manifest/validator.go
new file mode 100644
index 0000000..6e00347
--- /dev/null
+++ b/internal/manifest/validator.go
@@ -0,0 +1,159 @@
+package manifest
+
+import (
+	"errors"
+	"fmt"
+)
+
+// ErrIncompleteManifest is returned when a required manifest field is missing.
+var ErrIncompleteManifest = errors.New("incomplete manifest")
+
+// Validator validates that a RunManifest is complete before execution.
+type Validator struct {
+	requiredFields []string
+}
+
+// NewValidator creates a new manifest validator with default required fields.
+func NewValidator() *Validator {
+	return &Validator{
+		requiredFields: []string{
+			"commit_id",
+			"deps_manifest_sha256",
+		},
+	}
+}
+
+// NewValidatorWithFields creates a validator with custom required fields.
+func NewValidatorWithFields(fields []string) *Validator {
+	return &Validator{
+		requiredFields: fields,
+	}
+}
+
+// ValidationError contains details about a validation failure.
+type ValidationError struct {
+	Field   string `json:"field"`
+	Message string `json:"message"`
+}
+
+// Error returns the error string.
+func (e ValidationError) Error() string {
+	return fmt.Sprintf("validation error for field '%s': %s", e.Field, e.Message)
+}
+
+// Validate checks that the manifest has all required fields.
+// Returns an error listing all missing fields.
+func (v *Validator) Validate(m *RunManifest) error {
+	if m == nil {
+		return fmt.Errorf("manifest is nil: %w", ErrIncompleteManifest)
+	}
+
+	var validationErrors []ValidationError
+
+	for _, field := range v.requiredFields {
+		if err := v.validateField(m, field); err != nil {
+			validationErrors = append(validationErrors, *err)
+		}
+	}
+
+	if len(validationErrors) > 0 {
+		// Build comprehensive error message
+		msg := "manifest validation failed:\n"
+		for _, err := range validationErrors {
+			msg += fmt.Sprintf("  - %s\n", err.Error())
+		}
+		return fmt.Errorf("%s: %w", msg, ErrIncompleteManifest)
+	}
+
+	return nil
+}
+
+// ValidateStrict fails if ANY optional fields commonly used for provenance are missing.
+// This is for high-assurance environments.
+func (v *Validator) ValidateStrict(m *RunManifest) error {
+	if err := v.Validate(m); err != nil {
+		return err
+	}
+
+	// Additional strict checks
+	var strictErrors []ValidationError
+
+	if m.WorkerVersion == "" {
+		strictErrors = append(strictErrors, ValidationError{
+			Field:   "worker_version",
+			Message: "required for strict provenance",
+		})
+	}
+
+	if m.PodmanImage == "" {
+		strictErrors = append(strictErrors, ValidationError{
+			Field:   "podman_image",
+			Message: "required for strict provenance",
+		})
+	}
+
+	if len(strictErrors) > 0 {
+		msg := "strict manifest validation failed:\n"
+		for _, err := range strictErrors {
+			msg += fmt.Sprintf("  - %s\n", err.Error())
+		}
+		return fmt.Errorf("%s: %w", msg, ErrIncompleteManifest)
+	}
+
+	return nil
+}
+
+// validateField checks a single required field.
+func (v *Validator) validateField(m *RunManifest, field string) *ValidationError {
+	switch field {
+	case "commit_id":
+		if m.CommitID == "" {
+			return &ValidationError{
+				Field:   field,
+				Message: "commit_id is required for code provenance",
+			}
+		}
+	case "deps_manifest_sha256":
+		if m.DepsManifestSHA == "" {
+			return &ValidationError{
+				Field:   field,
+				Message: "deps_manifest_sha256 is required for dependency provenance",
+			}
+		}
+	case "run_id":
+		if m.RunID == "" {
+			return &ValidationError{
+				Field:   field,
+				Message: "run_id is required",
+			}
+		}
+	case "task_id":
+		if m.TaskID == "" {
+			return &ValidationError{
+				Field:   field,
+				Message: "task_id is required",
+			}
+		}
+	case "job_name":
+		if m.JobName == "" {
+			return &ValidationError{
+				Field:   field,
+				Message: "job_name is required",
+			}
+		}
+	case "snapshot_sha256":
+		if m.SnapshotID != "" && m.SnapshotSHA256 == "" {
+			return &ValidationError{
+				Field:   field,
+				Message: "snapshot_sha256 is required when snapshot_id is provided",
+			}
+		}
+	}
+
+	return nil
+}
+
+// IsValidationError checks if an error is a manifest validation error.
+func IsValidationError(err error) bool {
+	return errors.Is(err, ErrIncompleteManifest)
+}
diff --git a/internal/queue/queue_spec_test.go b/internal/queue/queue_spec_test.go
new file mode 100644
index 0000000..67067c5
--- /dev/null
+++ b/internal/queue/queue_spec_test.go
@@ -0,0 +1,188 @@
+package queue
+
+import (
+	"testing"
+	"time"
+)
+
+// TestTaskPrioritizationSpec documents the scheduler's priority and FIFO behavior.
+// These tests serve as executable specifications for the queue system.
+func TestTaskPrioritizationSpec(t *testing.T) {
+	tests := []struct {
+		name     string
+		tasks    []Task
+		expected []string // IDs in expected execution order
+	}{
+		{
+			name: "higher priority runs first",
+			tasks: []Task{
+				{ID: "low", Priority: 1, CreatedAt: time.Unix(100, 0)},
+				{ID: "high", Priority: 10, CreatedAt: time.Unix(100, 0)},
+			},
+			expected: []string{"high", "low"},
+		},
+		{
+			name: "FIFO for same priority",
+			tasks: []Task{
+				{ID: "first", Priority: 5, CreatedAt: time.Unix(100, 0)},
+				{ID: "second", Priority: 5, CreatedAt: time.Unix(200, 0)},
+			},
+			expected: []string{"first", "second"},
+		},
+		{
+			name: "mixed priorities and creation times",
+			tasks: []Task{
+				{ID: "medium-early", Priority: 5, CreatedAt: time.Unix(100, 0)},
+				{ID: "high-late", Priority: 10, CreatedAt: time.Unix(300, 0)},
+				{ID: "low-early", Priority: 1, CreatedAt: time.Unix(50, 0)},
+			},
+			expected: []string{"high-late", "medium-early", "low-early"},
+		},
+		{
+			name: "negative priority is lowest",
+			tasks: []Task{
+				{ID: "negative", Priority: -1, CreatedAt: time.Unix(100, 0)},
+				{ID: "positive", Priority: 1, CreatedAt: time.Unix(100, 0)},
+			},
+			expected: []string{"positive", "negative"},
+		},
+		{
+			name: "zero priority is default",
+			tasks: []Task{
+				{ID: "zero", Priority: 0, CreatedAt: time.Unix(100, 0)},
+				{ID: "positive", Priority: 1, CreatedAt: time.Unix(100, 0)},
+			},
+			expected: []string{"positive", "zero"},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Create a queue and add tasks
+			tmpDir := t.TempDir()
+			q, err := NewFilesystemQueue(tmpDir)
+			if err != nil {
+				t.Fatalf("failed to create queue: %v", err)
+			}
+			defer q.Close()
+
+			// Add all tasks
+			for _, task := range tt.tasks {
+				task := task // capture range variable
+				if err := q.AddTask(&task); err != nil {
+					t.Fatalf("failed to add task %s: %v", task.ID, err)
+				}
+			}
+
+			// Get tasks in order and verify
+			var actual []string
+			for i := 0; i < len(tt.tasks); i++ {
+				task, err := q.GetNextTask()
+				if err != nil {
+					t.Fatalf("failed to get task at position %d: %v", i, err)
+				}
+				if task == nil {
+					t.Fatalf("expected task at position %d, got nil", i)
+				}
+				actual = append(actual, task.ID)
+			}
+
+			// Verify order
+			if len(actual) != len(tt.expected) {
+				t.Errorf("expected %d tasks, got %d", len(tt.expected), len(actual))
+			}
+			for i, expectedID := range tt.expected {
+				if i >= len(actual) {
+					break
+				}
+				if actual[i] != expectedID {
+					t.Errorf("position %d: expected %s, got %s", i, expectedID, actual[i])
+				}
+			}
+		})
+	}
+}
+
+// TestQueueSpec_ClaimAndComplete documents the claim-complete lifecycle
+func TestQueueSpec_ClaimAndComplete(t *testing.T) {
+	tmpDir := t.TempDir()
+	q, err := NewFilesystemQueue(tmpDir)
+	if err != nil {
+		t.Fatalf("failed to create queue: %v", err)
+	}
+	defer q.Close()
+
+	// Add a task
+	task := &Task{
+		ID:        "task-1",
+		JobName:   "test-job",
+		Priority:  5,
+		CreatedAt: time.Now(),
+	}
+	if err := q.AddTask(task); err != nil {
+		t.Fatalf("failed to add task: %v", err)
+	}
+
+	// Get the task
+	claimed, err := q.GetNextTask()
+	if err != nil {
+		t.Fatalf("failed to get task: %v", err)
+	}
+	if claimed == nil {
+		t.Fatal("expected to claim a task, got nil")
+	}
+	if claimed.ID != task.ID {
+		t.Errorf("expected task %s, got %s", task.ID, claimed.ID)
+	}
+
+	// Verify task is no longer in queue
+	tasks, err := q.GetAllTasks()
+	if err != nil {
+		t.Fatalf("failed to get tasks: %v", err)
+	}
+	for _, tsk := range tasks {
+		if tsk.ID == task.ID {
+			t.Error("claimed task should not be in queue")
+		}
+	}
+}
+
+// TestQueueSpec_TaskPriorityOrdering documents numeric priority ordering
+func TestQueueSpec_TaskPriorityOrdering(t *testing.T) {
+	tmpDir := t.TempDir()
+	q, err := NewFilesystemQueue(tmpDir)
+	if err != nil {
+		t.Fatalf("failed to create queue: %v", err)
+	}
+	defer q.Close()
+
+	// Add tasks with various priorities
+	priorities := []int64{100, 50, 200, 1, 75}
+	for i, p := range priorities {
+		task := &Task{
+			ID:        "task-" + string(rune('a'+i)),
+			JobName:   "job-" + string(rune('a'+i)),
+			Priority:  p,
+			CreatedAt: time.Now(),
+		}
+		if err := q.AddTask(task); err != nil {
+			t.Fatalf("failed to add task: %v", err)
+		}
+	}
+
+	// Expected order: 200, 100, 75, 50, 1 (descending)
+	expected := []string{"task-c", "task-a", "task-e", "task-b", "task-d"}
+
+	for i, expID := range expected {
+		task, err := q.GetNextTask()
+		if err != nil {
+			t.Fatalf("position %d: failed to get task: %v", i, err)
+		}
+		if task == nil {
+			t.Fatalf("position %d: expected task %s, got nil", i, expID)
+		}
+		if task.ID != expID {
+			t.Errorf("position %d: expected %s, got %s", i, expID, task.ID)
+		}
+	}
+}
diff --git a/internal/worker/executor/runner.go b/internal/worker/executor/runner.go
index 9ed2caf..4e308f4 100644
--- a/internal/worker/executor/runner.go
+++ b/internal/worker/executor/runner.go
@@ -80,6 +80,27 @@ func (r *JobRunner) Run(
 	// 3. Select executor
 	executor := r.selectExecutor(mode, localMode)
 
+	// 3.5 Validate manifest completeness before execution
+	if r.writer != nil {
+		// Load current manifest and validate
+		if m, err := manifest.LoadFromDir(outputDir); err == nil {
+			validator := manifest.NewValidator()
+			if err := validator.Validate(m); err != nil {
+				r.logger.Error("manifest validation failed - execution blocked",
+					"task", task.ID,
+					"error", err)
+				return &errtypes.TaskExecutionError{
+					TaskID:      task.ID,
+					JobName:     task.JobName,
+					Phase:       "validation",
+					Message:     "manifest incomplete - execution blocked",
+					Err:         err,
+					Recoverable: false, // Can't retry - manifest is missing data
+				}
+			}
+		}
+	}
+
 	// 4. Pre-execution manifest update
 	if r.writer != nil {
 		r.writer.Upsert(outputDir, task, func(m *manifest.RunManifest) {
diff --git a/podman/hermetic.dockerfile b/podman/hermetic.dockerfile
new file mode 100644
index 0000000..a940ca7
--- /dev/null
+++ b/podman/hermetic.dockerfile
@@ -0,0 +1,40 @@
+# Hermetic Dockerfile - Reproducible builds with pinned dependencies
+# Tag image with: deps-<first-8-of-sha256>
+# Example: docker build -t mylab/pytorch:deps-abc123 .
+
+FROM pytorch/pytorch:2.0.1-cuda11.8-cudnn8-runtime
+
+# Pin system dependencies to specific versions for reproducibility
+# These versions are frozen - update only after testing
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    libblas3=3.9.0-1build1 \
+    liblapack3=3.9.0-1build1 \
+    libcudnn8=8.6.0.163-1+cuda11.8 \
+    && rm -rf /var/lib/apt/lists/*
+
+# Install conda environment with pinned packages
+COPY deps_manifest.json /tmp/deps_manifest.json
+
+# If using conda environment file
+RUN if [ -f /tmp/deps_manifest.json ]; then \
+        conda env update -n base -f /tmp/deps_manifest.json; \
+    fi
+
+# If using requirements.txt with hashes
+COPY requirements.txt /tmp/requirements.txt
+RUN pip install --require-hashes --no-deps -r /tmp/requirements.txt \
+    || echo "Warning: Some packages may not have hashes"
+
+# Verify installation
+RUN python -c "import torch; print(f'PyTorch: {torch.__version__}')" \
+    && python -c "import numpy; print(f'NumPy: {numpy.__version__}')"
+
+# Labels for provenance
+LABEL org.opencontainers.image.title="Hermetic ML Environment" \
+      org.opencontainers.image.description="Reproducible ML training environment" \
+      org.fetchml.deps_manifest="/tmp/deps_manifest.json" \
+      org.fetchml.build_date="${BUILD_DATE}" \
+      org.fetchml.git_commit="${GIT_COMMIT}"
+
+WORKDIR /workspace
+CMD ["python", "--version"]