diff --git a/static/ast-parser.js b/static/ast-parser.js
index d5365c0..fa6aa4f 100644
--- a/static/ast-parser.js
+++ b/static/ast-parser.js
@@ -118,24 +118,47 @@ export function buildModel(rawTree) {
         info: null,
         tuning: null,
         articles: [],
+        stageCone: null,
         stageVoices: [],
         instruments: [],
         bars: [],
     };
 
+    // Upstream uses `with deeper_level("articles"):` / `deeper_level("stage"):`
+    // implicit containers that emit no depth-00 header. Their depth-01 lines get
+    // nested under the preceding `00 tuning` by the depth-stack parser even
+    // though they are conceptually siblings of tuning. Un-nest them here.
+    const topLevel = [];
     for (const node of rawTree.children) {
-        switch (node.slot) {
+        if (node.parentSlot === null && node.slot === 'tuning') {
+            const trulyTuning = [];
+            const misnested = [];
+            for (const child of node.children) {
+                if (child.parentSlot === 'tuning') trulyTuning.push(child);
+                else misnested.push(child);
+            }
+            topLevel.push({ ...node, children: trulyTuning });
+            topLevel.push(...misnested);
+        } else {
+            topLevel.push(node);
+        }
+    }
+
+    for (const node of topLevel) {
+        const fqSlot = node.parentSlot ? `${node.parentSlot}.${node.slot}` : node.slot;
+        switch (fqSlot) {
             case 'info':
                 score.info = { ...node.props };
                 break;
             case 'tuning':
                 score.tuning = buildTuning(node);
                 break;
-            case 'article':
-                score.articles.push(buildArticle(node));
+            case 'stage.cone':
+                score.stageCone = { type: 'stage_cone', ...node.props };
                 break;
-            case 'stage_voice':
+            case 'stage.voice':
                 score.stageVoices.push({
+                    type: 'stage_voice',
                     name: node.positionals[0],
                     direction: node.props.direction,
                     distance: node.props.distance,
@@ -148,7 +171,11 @@ export function buildModel(rawTree) {
                 score.bars.push(buildBar(node));
                 break;
             default:
-                score[node.slot] = buildGeneric(node);
+                if (node.parentSlot === 'articles') {
+                    score.articles.push(buildArticle(node));
+                } else {
+                    score[node.slot] = buildGeneric(node);
+                }
         }
     }
 
@@ -156,12 +183,17 @@ export function buildModel(rawTree) {
 }
 
 function buildTuning(node) {
-    const t = { base: node.props.base, scales: {}, chords: {} };
+    const t = { type: 'tuning', base: node.props.base, scales: {}, chords: {}, frequencyFactors: null };
     for (const child of node.children) {
         if (child.slot === 'scales') {
             t.scales[child.positionals[0]] = child.positionals.slice(1);
         } else if (child.slot === 'chords') {
             t.chords[child.positionals[0]] = child.positionals.slice(1);
+        } else if (child.slot === 'frequency_factors') {
+            t.frequencyFactors = {
+                label: child.props.label ?? null,
+                factors: child.positionals.slice(),
+            };
         }
     }
     return t;
@@ -170,11 +202,9 @@ function buildTuning(node) {
 function buildArticle(node) {
     return {
         type: 'article',
+        subtype: node.slot,
         name: node.positionals[0],
         props: { ...node.props },
-        properties: node.children
-            .filter(c => c.slot === 'property')
-            .map(c => ({ name: c.positionals[0], ...c.props })),
     };
 }
 
diff --git a/test-parser.mjs b/test-parser.mjs
index bf2b32b..d8ab448 100644
--- a/test-parser.mjs
+++ b/test-parser.mjs
@@ -31,6 +31,27 @@ ok('has bars', model.bars.length > 0);
 ok('432 bars', model.bars.length === 432);
 console.log(`     bars: ${model.bars.length}, instruments: ${model.instruments.length}`);
 
+// ── Preamble (info, tuning, stage, articles) ───────────────────────────────
+section('Preamble');
+ok('info parsed',                    model.info && typeof model.info.title === 'string');
+ok('info composer',                  model.info?.composer === 'Ludwig van Beethoven');
+ok('tuning parsed',                  model.tuning && model.tuning.base === 'tones_euro_de+en');
+ok('tuning has scales',              Object.keys(model.tuning.scales).length > 0);
+ok('tuning.scales hm7',              Array.isArray(model.tuning.scales.hm7));
+ok('tuning has chords',              Object.keys(model.tuning.chords).length > 0);
+ok('tuning frequencyFactors object', model.tuning.frequencyFactors && typeof model.tuning.frequencyFactors === 'object');
+ok('frequencyFactors label',         model.tuning.frequencyFactors.label === 'just5lim');
+ok('frequencyFactors 12 ratios',     model.tuning.frequencyFactors.factors.length === 12);
+ok('stageCone parsed',               model.stageCone && model.stageCone.type === 'stage_cone');
+ok('stageCone has minvol',           model.stageCone.minvol !== undefined);
+ok('stageVoices parsed',             model.stageVoices.length === 3);
+ok('stageVoices[0] is "pi"',         model.stageVoices[0].name === 'pi');
+ok('stageVoices[0].direction',       model.stageVoices[0].direction === '1|1');
+ok('articles array non-empty',       model.articles.length > 0);
+ok('articles[0].subtype defaults',   model.articles[0].subtype === 'defaults');
+ok('articles[0].name "f"',           model.articles[0].name === 'f');
+ok('articles[0].props.add_stress',   model.articles[0].props.add_stress === 3);
+
 // ── Bar IDs ────────────────────────────────────────────────────────────────
 // Bar IDs are opaque auto-increment strings; only the raw id string matters.
 section('Bar IDs');