diff --git a/package-lock.json b/package-lock.json
index 6aead423..0a10c5b3 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "scale-workshop",
-  "version": "3.0.0-beta.13",
+  "version": "3.0.0-beta.14",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "scale-workshop",
-      "version": "3.0.0-beta.13",
+      "version": "3.0.0-beta.14",
       "dependencies": {
         "isomorphic-qwerty": "^0.0.2",
         "ji-lattice": "^0.0.3",
@@ -14,7 +14,7 @@
         "moment-of-symmetry": "^0.4.2",
         "pinia": "^2.1.7",
         "qs": "^6.12.0",
-        "sonic-weave": "github:xenharmonic-devs/sonic-weave#v0.0.17",
+        "sonic-weave": "github:xenharmonic-devs/sonic-weave#v0.0.20",
         "sw-synth": "^0.1.0",
         "temperaments": "^0.5.3",
         "vue": "^3.3.4",
@@ -5400,8 +5400,8 @@
       }
     },
     "node_modules/sonic-weave": {
-      "version": "0.0.17",
-      "resolved": "git+ssh://git@github.com/xenharmonic-devs/sonic-weave.git#0033a815351b713c76da1da7ca46550065d9b230",
+      "version": "0.0.20",
+      "resolved": "git+ssh://git@github.com/xenharmonic-devs/sonic-weave.git#7d5a97f82ce23a4316a0cf71ab831106f73a7eb5",
       "license": "MIT",
       "dependencies": {
         "moment-of-symmetry": "^0.4.2",
diff --git a/package.json b/package.json
index 85e45ef3..fda1d654 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "scale-workshop",
-  "version": "3.0.0-beta.13",
+  "version": "3.0.0-beta.14",
   "scripts": {
     "dev": "vite",
     "build": "run-p type-check \"build-only {@}\" --",
@@ -21,7 +21,7 @@
     "moment-of-symmetry": "^0.4.2",
     "pinia": "^2.1.7",
     "qs": "^6.12.0",
-    "sonic-weave": "github:xenharmonic-devs/sonic-weave#v0.0.17",
+    "sonic-weave": "github:xenharmonic-devs/sonic-weave#v0.0.20",
     "sw-synth": "^0.1.0",
     "temperaments": "^0.5.3",
     "vue": "^3.3.4",
diff --git a/src/components/modals/modification/CoalesceDuplicates.vue b/src/components/modals/modification/CoalesceDuplicates.vue
index ede92711..855efaf9 100644
--- a/src/components/modals/modification/CoalesceDuplicates.vue
+++ b/src/components/modals/modification/CoalesceDuplicates.vue
@@ -10,7 +10,7 @@ const modal = useModalStore()
 const scale = useScaleStore()
 
 function modify(expand = true) {
-  scale.sourceText += `\ncoalesce(${centString(modal.tolerance)}, '${modal.coalescingAction}')`
+  scale.sourceText += `\ncoalesce(${centString(modal.tolerance)}, '${modal.coalescingAction}', ${modal.preserveBoundary})`
   if (expand) {
     const { visitor, defaults } = scale.getVisitors()
     scale.sourceText = visitor.expand(defaults)
@@ -93,6 +93,10 @@ function modify(expand = true) {
             <label for="action-geoavg">Geometric</label>
           </span>
         </div>
+        <div class="control checkbox-container">
+          <input type="checkbox" id="preserve-boundary" v-model="modal.preserveBoundary" />
+          <label for="preserve-boundary">Preserve small intervals near unison</label>
+        </div>
       </div>
     </template>
     <template #footer>
diff --git a/src/stores/modal.ts b/src/stores/modal.ts
index b7bfbafa..acbae2a5 100644
--- a/src/stores/modal.ts
+++ b/src/stores/modal.ts
@@ -449,6 +449,7 @@ export const useModalStore = defineStore('modal', () => {
   const coalescingAction = ref<'avg' | 'havg' | 'geoavg' | 'lowest' | 'highest' | 'simplest'>(
     'simplest'
   )
+  const preserveBoundary = ref(false)
 
   // Concordance shell
   const mediumInteger = ref(32)
@@ -627,6 +628,7 @@ export const useModalStore = defineStore('modal', () => {
     // Coalesce
     tolerance,
     coalescingAction,
+    preserveBoundary,
 
     // Expand
     simplify,
diff --git a/src/stores/scale.ts b/src/stores/scale.ts
index 43effe68..b953fa25 100644
--- a/src/stores/scale.ts
+++ b/src/stores/scale.ts
@@ -315,7 +315,7 @@ export const useScaleStore = defineStore('scale', () => {
       warn
     }
     const visitor = getSourceVisitor(true, extraBuiltins)
-    visitor.rootContext.gas = gas.value
+    visitor.rootContext!.gas = gas.value
 
     // Declare base nominal and unison frequency
     const prefixAst = parseAST(sourcePrefix.value)
@@ -329,8 +329,8 @@ export const useScaleStore = defineStore('scale', () => {
   // Methods
   function getVisitors() {
     const globalVisitor = getGlobalVisitor()
-    const visitor = new StatementVisitor(globalVisitor.rootContext, globalVisitor)
-    const defaults = visitor.rootContext.clone()
+    const visitor = new StatementVisitor(globalVisitor)
+    const defaults = visitor.rootContext!.clone()
     defaults.gas = gas.value
 
     const ast = parseAST(sourceText.value)
@@ -352,7 +352,7 @@ export const useScaleStore = defineStore('scale', () => {
       warning.value = ''
       latticeIntervals.value = []
       const globalVisitor = getGlobalVisitor()
-      const visitor = new StatementVisitor(globalVisitor.rootContext, globalVisitor)
+      const visitor = new StatementVisitor(globalVisitor)
       const ast = parseAST(sourceText.value)
       let userDeclaredPitch = false
       for (const statement of ast.body) {
@@ -374,8 +374,8 @@ export const useScaleStore = defineStore('scale', () => {
       }
       const ratios = relativeIntervals.value.map((i) => i.value.valueOf())
       let visitorBaseFrequency = mtof(baseMidiNote.value)
-      if (visitor.rootContext.unisonFrequency) {
-        visitorBaseFrequency = visitor.rootContext.unisonFrequency.valueOf()
+      if (visitor.rootContext!.unisonFrequency) {
+        visitorBaseFrequency = visitor.rootContext!.unisonFrequency.valueOf()
       }
       if (ratios.length) {
         const name = str.bind(ev)
diff --git a/src/utils.ts b/src/utils.ts
index 3be3ddb4..a0d0e3a5 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -61,8 +61,8 @@ export function splitText(text: string) {
 
 export function expandCode(source: string) {
   const globalVisitor = getSourceVisitor()
-  const defaults = globalVisitor.rootContext.clone()
-  const visitor = new StatementVisitor(globalVisitor.rootContext, globalVisitor)
+  const defaults = globalVisitor.rootContext!.clone()
+  const visitor = new StatementVisitor(globalVisitor)
   const ast = parseAST(source)
   for (const statement of ast.body) {
     const interupt = visitor.visit(statement)