diff --git a/src/domain/graph/builder/incremental.js b/src/domain/graph/builder/incremental.js
index 778356242..2be5cefa5 100644
--- a/src/domain/graph/builder/incremental.js
+++ b/src/domain/graph/builder/incremental.js
@@ -3,9 +3,13 @@
  *
  * Reuses pipeline helpers instead of duplicating node insertion and edge building
  * logic from the main builder. This eliminates the watcher.js divergence (ROADMAP 3.9).
+ *
+ * Reverse-dep cascade: when a file changes, files that have edges targeting it
+ * must have their outgoing edges rebuilt (since the changed file's node IDs change).
  */
 import fs from 'node:fs';
 import path from 'node:path';
+import { bulkNodeIdsByFile } from '../../../db/index.js';
 import { warn } from '../../../infrastructure/logger.js';
 import { normalizePath } from '../../../shared/constants.js';
 import { parseFileIncremental } from '../../parser.js';
@@ -18,15 +22,252 @@ function insertFileNodes(stmts, relPath, symbols) {
   stmts.insertNode.run(relPath, 'file', relPath, 0, null);
   for (const def of symbols.definitions) {
     stmts.insertNode.run(def.name, def.kind, relPath, def.line, def.endLine || null);
+    if (def.children?.length) {
+      for (const child of def.children) {
+        stmts.insertNode.run(child.name, child.kind, relPath, child.line, child.endLine || null);
+      }
+    }
   }
   for (const exp of symbols.exports) {
     stmts.insertNode.run(exp.name, exp.kind, relPath, exp.line, null);
   }
 }
 
+// ── Containment edges ──────────────────────────────────────────────────
+
+function buildContainmentEdges(db, stmts, relPath, symbols) {
+  const nodeIdMap = new Map();
+  for (const row of bulkNodeIdsByFile(db, relPath)) {
+    nodeIdMap.set(`${row.name}|${row.kind}|${row.line}`, row.id);
+  }
+  const fileId = nodeIdMap.get(`${relPath}|file|0`);
+  let edgesAdded = 0;
+  for (const def of symbols.definitions) {
+    const defId = nodeIdMap.get(`${def.name}|${def.kind}|${def.line}`);
+    if (fileId && defId) {
+      stmts.insertEdge.run(fileId, defId, 'contains', 1.0, 0);
+      edgesAdded++;
+    }
+    if (def.children?.length && defId) {
+      for (const child of def.children) {
+        const childId = nodeIdMap.get(`${child.name}|${child.kind}|${child.line}`);
+        if (childId) {
+          stmts.insertEdge.run(defId, childId, 'contains', 1.0, 0);
+          edgesAdded++;
+          if (child.kind === 'parameter') {
+            stmts.insertEdge.run(childId, defId, 'parameter_of', 1.0, 0);
+            edgesAdded++;
+          }
+        }
+      }
+    }
+  }
+  return edgesAdded;
+}
+
+// ── Reverse-dep cascade ────────────────────────────────────────────────
+
+// Lazily-cached prepared statements for reverse-dep operations
+let _revDepDb = null;
+let _findRevDepsStmt = null;
+let _deleteOutEdgesStmt = null;
+
+function getRevDepStmts(db) {
+  if (_revDepDb !== db) {
+    _revDepDb = db;
+    _findRevDepsStmt = db.prepare(
+      `SELECT DISTINCT n_src.file FROM edges e
+       JOIN nodes n_src ON e.source_id = n_src.id
+       JOIN nodes n_tgt ON e.target_id = n_tgt.id
+       WHERE n_tgt.file = ? AND n_src.file != ? AND n_src.kind != 'directory'`,
+    );
+    _deleteOutEdgesStmt = db.prepare(
+      'DELETE FROM edges WHERE source_id IN (SELECT id FROM nodes WHERE file = ?)',
+    );
+  }
+  return { findRevDepsStmt: _findRevDepsStmt, deleteOutEdgesStmt: _deleteOutEdgesStmt };
+}
+
+function findReverseDeps(db, relPath) {
+  const { findRevDepsStmt } = getRevDepStmts(db);
+  return findRevDepsStmt.all(relPath, relPath).map((r) => r.file);
+}
+
+function deleteOutgoingEdges(db, relPath) {
+  const { deleteOutEdgesStmt } = getRevDepStmts(db);
+  deleteOutEdgesStmt.run(relPath);
+}
+
+async function parseReverseDep(rootDir, depRelPath, engineOpts, cache) {
+  const absPath = path.join(rootDir, depRelPath);
+  if (!fs.existsSync(absPath)) return null;
+
+  let code;
+  try {
+    code = readFileSafe(absPath);
+  } catch {
+    return null;
+  }
+
+  return parseFileIncremental(cache, absPath, code, engineOpts);
+}
+
+function rebuildReverseDepEdges(db, rootDir, depRelPath, symbols, stmts, skipBarrel) {
+  const fileNodeRow = stmts.getNodeId.get(depRelPath, 'file', depRelPath, 0);
+  if (!fileNodeRow) return 0;
+
+  const aliases = { baseUrl: null, paths: {} };
+  let edgesAdded = buildContainmentEdges(db, stmts, depRelPath, symbols);
+  // Don't rebuild dir→file containment for reverse-deps (it was never deleted)
+  edgesAdded += buildImportEdges(
+    stmts,
+    depRelPath,
+    symbols,
+    rootDir,
+    fileNodeRow.id,
+    aliases,
+    skipBarrel ? null : db,
+  );
+  const importedNames = buildImportedNamesMap(symbols, rootDir, depRelPath, aliases);
+  edgesAdded += buildCallEdges(stmts, depRelPath, symbols, fileNodeRow, importedNames);
+  return edgesAdded;
+}
+
+// ── Directory containment edges ────────────────────────────────────────
+
+function rebuildDirContainment(_db, stmts, relPath) {
+  const dir = normalizePath(path.dirname(relPath));
+  if (!dir || dir === '.') return 0;
+  const dirRow = stmts.getNodeId.get(dir, 'directory', dir, 0);
+  const fileRow = stmts.getNodeId.get(relPath, 'file', relPath, 0);
+  if (dirRow && fileRow) {
+    stmts.insertEdge.run(dirRow.id, fileRow.id, 'contains', 1.0, 0);
+    return 1;
+  }
+  return 0;
+}
+
+// ── Ancillary table cleanup ────────────────────────────────────────────
+
+function purgeAncillaryData(db, relPath) {
+  const tryExec = (sql, ...args) => {
+    try {
+      db.prepare(sql).run(...args);
+    } catch (err) {
+      if (!err?.message?.includes('no such table')) throw err;
+    }
+  };
+  tryExec(
+    'DELETE FROM function_complexity WHERE node_id IN (SELECT id FROM nodes WHERE file = ?)',
+    relPath,
+  );
+  tryExec(
+    'DELETE FROM node_metrics WHERE node_id IN (SELECT id FROM nodes WHERE file = ?)',
+    relPath,
+  );
+  tryExec(
+    'DELETE FROM cfg_edges WHERE function_node_id IN (SELECT id FROM nodes WHERE file = ?)',
+    relPath,
+  );
+  tryExec(
+    'DELETE FROM cfg_blocks WHERE function_node_id IN (SELECT id FROM nodes WHERE file = ?)',
+    relPath,
+  );
+  tryExec(
+    'DELETE FROM dataflow WHERE source_id IN (SELECT id FROM nodes WHERE file = ?) OR target_id IN (SELECT id FROM nodes WHERE file = ?)',
+    relPath,
+    relPath,
+  );
+  tryExec('DELETE FROM ast_nodes WHERE file = ?', relPath);
+}
+
 // ── Import edge building ────────────────────────────────────────────────
 
-function buildImportEdges(stmts, relPath, symbols, rootDir, fileNodeId, aliases) {
+// Lazily-cached prepared statements for barrel resolution (avoid re-preparing in hot loops)
+let _barrelDb = null;
+let _isBarrelStmt = null;
+let _reexportTargetsStmt = null;
+let _hasDefStmt = null;
+
+function getBarrelStmts(db) {
+  if (_barrelDb !== db) {
+    _barrelDb = db;
+    _isBarrelStmt = db.prepare(
+      `SELECT COUNT(*) as c FROM edges e
+       JOIN nodes n ON e.source_id = n.id
+       WHERE e.kind = 'reexports' AND n.file = ? AND n.kind = 'file'`,
+    );
+    _reexportTargetsStmt = db.prepare(
+      `SELECT DISTINCT n2.file FROM edges e
+       JOIN nodes n1 ON e.source_id = n1.id
+       JOIN nodes n2 ON e.target_id = n2.id
+       WHERE e.kind = 'reexports' AND n1.file = ? AND n1.kind = 'file'`,
+    );
+    _hasDefStmt = db.prepare(
+      `SELECT 1 FROM nodes WHERE name = ? AND file = ? AND kind != 'file' AND kind != 'directory' LIMIT 1`,
+    );
+  }
+  return {
+    isBarrelStmt: _isBarrelStmt,
+    reexportTargetsStmt: _reexportTargetsStmt,
+    hasDefStmt: _hasDefStmt,
+  };
+}
+
+function isBarrelFile(db, relPath) {
+  const { isBarrelStmt } = getBarrelStmts(db);
+  const reexportCount = isBarrelStmt.get(relPath)?.c;
+  return (reexportCount || 0) > 0;
+}
+
+function resolveBarrelTarget(db, barrelPath, symbolName, visited = new Set()) {
+  if (visited.has(barrelPath)) return null;
+  visited.add(barrelPath);
+
+  const { reexportTargetsStmt, hasDefStmt } = getBarrelStmts(db);
+
+  // Find re-export targets from this barrel
+  const reexportTargets = reexportTargetsStmt.all(barrelPath);
+
+  for (const { file: targetFile } of reexportTargets) {
+    // Check if the symbol is defined in this target file
+    const hasDef = hasDefStmt.get(symbolName, targetFile);
+    if (hasDef) return targetFile;
+
+    // Recurse through barrel chains
+    if (isBarrelFile(db, targetFile)) {
+      const deeper = resolveBarrelTarget(db, targetFile, symbolName, visited);
+      if (deeper) return deeper;
+    }
+  }
+  return null;
+}
+
+/**
+ * Resolve barrel imports for a single import statement and create edges to actual source files.
+ * Shared by buildImportEdges (primary file) and Pass 2 of the reverse-dep cascade.
+ */
+function resolveBarrelImportEdges(db, stmts, fileNodeId, resolvedPath, imp) {
+  let edgesAdded = 0;
+  if (!isBarrelFile(db, resolvedPath)) return edgesAdded;
+  const resolvedSources = new Set();
+  for (const name of imp.names) {
+    const cleanName = name.replace(/^\*\s+as\s+/, '');
+    const actualSource = resolveBarrelTarget(db, resolvedPath, cleanName);
+    if (actualSource && actualSource !== resolvedPath && !resolvedSources.has(actualSource)) {
+      resolvedSources.add(actualSource);
+      const actualRow = stmts.getNodeId.get(actualSource, 'file', actualSource, 0);
+      if (actualRow) {
+        const kind = imp.typeOnly ? 'imports-type' : 'imports';
+        stmts.insertEdge.run(fileNodeId, actualRow.id, kind, 0.9, 0);
+        edgesAdded++;
+      }
+    }
+  }
+  return edgesAdded;
+}
+
+function buildImportEdges(stmts, relPath, symbols, rootDir, fileNodeId, aliases, db) {
   let edgesAdded = 0;
   for (const imp of symbols.imports) {
     const resolvedPath = resolveImportPath(
@@ -40,6 +281,11 @@ function buildImportEdges(stmts, relPath, symbols, rootDir, fileNodeId, aliases)
       const edgeKind = imp.reexport ? 'reexports' : imp.typeOnly ? 'imports-type' : 'imports';
       stmts.insertEdge.run(fileNodeId, targetRow.id, edgeKind, 1.0, 0);
       edgesAdded++;
+
+      // Barrel resolution: create edges through re-export chains
+      if (!imp.reexport && db) {
+        edgesAdded += resolveBarrelImportEdges(db, stmts, fileNodeId, resolvedPath, imp);
+      }
     }
   }
   return edgesAdded;
@@ -116,7 +362,13 @@ function resolveCallTargets(stmts, call, relPath, importedNames, typeMap) {
 }
 
 function buildCallEdges(stmts, relPath, symbols, fileNodeRow, importedNames) {
-  const typeMap = symbols.typeMap || new Map();
+  const rawTM = symbols.typeMap;
+  const typeMap =
+    rawTM instanceof Map
+      ? rawTM
+      : Array.isArray(rawTM) && rawTM.length > 0
+        ? new Map(rawTM.map((e) => [e.name, e.typeName ?? e.type ?? null]))
+        : new Map();
   let edgesAdded = 0;
   for (const call of symbols.calls) {
     if (call.receiver && BUILTIN_RECEIVERS.has(call.receiver)) continue;
@@ -146,7 +398,7 @@ function buildCallEdges(stmts, relPath, symbols, fileNodeRow, importedNames) {
 /**
  * Parse a single file and update the database incrementally.
  *
- * @param {import('better-sqlite3').Database} _db
+ * @param {import('better-sqlite3').Database} db
  * @param {string} rootDir - Absolute root directory
  * @param {string} filePath - Absolute file path
  * @param {object} stmts - Prepared DB statements
@@ -156,12 +408,17 @@ function buildCallEdges(stmts, relPath, symbols, fileNodeRow, importedNames) {
  * @param {Function} [options.diffSymbols] - Symbol diff function
  * @returns {Promise<object|null>} Update result or null on failure
  */
-export async function rebuildFile(_db, rootDir, filePath, stmts, engineOpts, cache, options = {}) {
+export async function rebuildFile(db, rootDir, filePath, stmts, engineOpts, cache, options = {}) {
   const { diffSymbols } = options;
   const relPath = normalizePath(path.relative(rootDir, filePath));
   const oldNodes = stmts.countNodes.get(relPath)?.c || 0;
   const oldSymbols = diffSymbols ? stmts.listSymbols.all(relPath) : [];
 
+  // Find reverse-deps BEFORE purging (edges still reference the old nodes)
+  const reverseDeps = findReverseDeps(db, relPath);
+
+  // Purge ancillary tables, then edges, then nodes
+  purgeAncillaryData(db, relPath);
   stmts.deleteEdgesForFile.run(relPath);
   stmts.deleteNodes.run(relPath);
 
@@ -203,10 +460,44 @@ export async function rebuildFile(_db, rootDir, filePath, stmts, engineOpts, cac
 
   const aliases = { baseUrl: null, paths: {} };
 
-  let edgesAdded = buildImportEdges(stmts, relPath, symbols, rootDir, fileNodeRow.id, aliases);
+  let edgesAdded = buildContainmentEdges(db, stmts, relPath, symbols);
+  edgesAdded += rebuildDirContainment(db, stmts, relPath);
+  edgesAdded += buildImportEdges(stmts, relPath, symbols, rootDir, fileNodeRow.id, aliases, db);
   const importedNames = buildImportedNamesMap(symbols, rootDir, relPath, aliases);
   edgesAdded += buildCallEdges(stmts, relPath, symbols, fileNodeRow, importedNames);
 
+  // Cascade: rebuild outgoing edges for reverse-dep files.
+  // Two-pass approach: first rebuild direct edges (creating reexports edges for barrels),
+  // then add barrel import edges (which need reexports edges to exist for resolution).
+  const depSymbols = new Map();
+  for (const depRelPath of reverseDeps) {
+    const symbols_ = await parseReverseDep(rootDir, depRelPath, engineOpts, cache);
+    if (symbols_) {
+      deleteOutgoingEdges(db, depRelPath);
+      depSymbols.set(depRelPath, symbols_);
+    }
+  }
+  // Pass 1: direct edges only (no barrel resolution) — creates reexports edges
+  for (const [depRelPath, symbols_] of depSymbols) {
+    edgesAdded += rebuildReverseDepEdges(db, rootDir, depRelPath, symbols_, stmts, true);
+  }
+  // Pass 2: add barrel import edges (reexports edges now exist)
+  for (const [depRelPath, symbols_] of depSymbols) {
+    const fileNodeRow_ = stmts.getNodeId.get(depRelPath, 'file', depRelPath, 0);
+    if (!fileNodeRow_) continue;
+    const aliases_ = { baseUrl: null, paths: {} };
+    for (const imp of symbols_.imports) {
+      if (imp.reexport) continue;
+      const resolvedPath = resolveImportPath(
+        path.join(rootDir, depRelPath),
+        imp.source,
+        rootDir,
+        aliases_,
+      );
+      edgesAdded += resolveBarrelImportEdges(db, stmts, fileNodeRow_.id, resolvedPath, imp);
+    }
+  }
+
   const symbolDiff = diffSymbols ? diffSymbols(oldSymbols, newSymbols) : null;
   const event = oldNodes === 0 ? 'added' : 'modified';
 
diff --git a/tests/benchmarks/resolution/fixtures/typescript/index.ts b/tests/benchmarks/resolution/fixtures/typescript/index.ts
index fcc349784..c9e591062 100644
--- a/tests/benchmarks/resolution/fixtures/typescript/index.ts
+++ b/tests/benchmarks/resolution/fixtures/typescript/index.ts
@@ -1,5 +1,5 @@
 import { JsonSerializer } from './serializer';
-import { createService, UserService } from './service';
+import { createService, type UserService } from './service';
 
 export function main(): void {
   const svc = createService();
diff --git a/tests/fixtures/deep-deps-project/app.js b/tests/fixtures/deep-deps-project/app.js
new file mode 100644
index 000000000..b557f27cd
--- /dev/null
+++ b/tests/fixtures/deep-deps-project/app.js
@@ -0,0 +1,9 @@
+import { formatOutput } from './features/format.js';
+import { runQuery } from './features/query.js';
+import { MAX_ITEMS } from './shared/constants.js';
+
+export function main(input, page) {
+  const results = runQuery(input, page);
+  const label = formatOutput(input);
+  return { label, results, max: MAX_ITEMS };
+}
diff --git a/tests/fixtures/deep-deps-project/domain/index.js b/tests/fixtures/deep-deps-project/domain/index.js
new file mode 100644
index 000000000..18ae4e72e
--- /dev/null
+++ b/tests/fixtures/deep-deps-project/domain/index.js
@@ -0,0 +1,2 @@
+export { parseItems } from './parser.js';
+export { resolve } from './resolver.js';
diff --git a/tests/fixtures/deep-deps-project/domain/parser.js b/tests/fixtures/deep-deps-project/domain/parser.js
new file mode 100644
index 000000000..b21ae1d1f
--- /dev/null
+++ b/tests/fixtures/deep-deps-project/domain/parser.js
@@ -0,0 +1,6 @@
+import { clamp, MAX_ITEMS } from '../shared/index.js';
+
+export function parseItems(raw) {
+  const items = raw.split(',').map((s) => s.trim());
+  return items.slice(0, clamp(items.length, 0, MAX_ITEMS));
+}
diff --git a/tests/fixtures/deep-deps-project/domain/resolver.js b/tests/fixtures/deep-deps-project/domain/resolver.js
new file mode 100644
index 000000000..619c2ca33
--- /dev/null
+++ b/tests/fixtures/deep-deps-project/domain/resolver.js
@@ -0,0 +1,7 @@
+import { DEFAULT_NAME } from '../shared/constants.js';
+import { formatName } from '../shared/helpers.js';
+
+export function resolve(input) {
+  const name = input || DEFAULT_NAME;
+  return formatName(name);
+}
diff --git a/tests/fixtures/deep-deps-project/features/format.js b/tests/fixtures/deep-deps-project/features/format.js
new file mode 100644
index 000000000..17e6419ea
--- /dev/null
+++ b/tests/fixtures/deep-deps-project/features/format.js
@@ -0,0 +1,7 @@
+import { resolve } from '../domain/resolver.js';
+import { DEFAULT_NAME } from '../shared/index.js';
+
+export function formatOutput(input) {
+  const resolved = resolve(input);
+  return resolved === DEFAULT_NAME ? 'default' : resolved;
+}
diff --git a/tests/fixtures/deep-deps-project/features/query.js b/tests/fixtures/deep-deps-project/features/query.js
new file mode 100644
index 000000000..216b23ac3
--- /dev/null
+++ b/tests/fixtures/deep-deps-project/features/query.js
@@ -0,0 +1,9 @@
+import { parseItems } from '../domain/index.js';
+import { clamp } from '../shared/constants.js';
+import { paginate } from '../shared/helpers.js';
+
+export function runQuery(raw, page) {
+  const items = parseItems(raw);
+  const safePage = clamp(page, 0, 100);
+  return paginate(items, safePage, 10);
+}
diff --git a/tests/fixtures/deep-deps-project/shared/constants.js b/tests/fixtures/deep-deps-project/shared/constants.js
new file mode 100644
index 000000000..8228aa8a5
--- /dev/null
+++ b/tests/fixtures/deep-deps-project/shared/constants.js
@@ -0,0 +1,7 @@
+// The deeply-imported leaf file
+export const MAX_ITEMS = 100;
+export const DEFAULT_NAME = 'codegraph';
+
+export function clamp(value, min, max) {
+  return Math.min(Math.max(value, min), max);
+}
diff --git a/tests/fixtures/deep-deps-project/shared/helpers.js b/tests/fixtures/deep-deps-project/shared/helpers.js
new file mode 100644
index 000000000..eeef13fbb
--- /dev/null
+++ b/tests/fixtures/deep-deps-project/shared/helpers.js
@@ -0,0 +1,11 @@
+import { clamp, MAX_ITEMS } from './constants.js';
+
+export function paginate(items, page, size) {
+  const safeSize = clamp(size, 1, MAX_ITEMS);
+  const start = page * safeSize;
+  return items.slice(start, start + safeSize);
+}
+
+export function formatName(name) {
+  return name.trim().toLowerCase();
+}
diff --git a/tests/fixtures/deep-deps-project/shared/index.js b/tests/fixtures/deep-deps-project/shared/index.js
new file mode 100644
index 000000000..b26feefbf
--- /dev/null
+++ b/tests/fixtures/deep-deps-project/shared/index.js
@@ -0,0 +1,2 @@
+export { clamp, DEFAULT_NAME, MAX_ITEMS } from './constants.js';
+export { formatName, paginate } from './helpers.js';
diff --git a/tests/integration/incr-edge-gap.test.js b/tests/integration/incr-edge-gap.test.js
new file mode 100644
index 000000000..0a4f4eb37
--- /dev/null
+++ b/tests/integration/incr-edge-gap.test.js
@@ -0,0 +1,137 @@
+/**
+ * Reproduction test for #533: incremental builds produce fewer edges than full builds.
+ * Uses a deeper dependency graph to exercise reverse-dep cascade.
+ */
+import fs from 'node:fs';
+import os from 'node:os';
+import path from 'node:path';
+import Database from 'better-sqlite3';
+import { describe, expect, it } from 'vitest';
+import { buildGraph } from '../../src/domain/graph/builder.js';
+
+const FIXTURE_DIR = path.join(import.meta.dirname, '..', 'fixtures', 'deep-deps-project');
+
+function copyDirSync(src, dest) {
+  fs.mkdirSync(dest, { recursive: true });
+  for (const entry of fs.readdirSync(src, { withFileTypes: true })) {
+    const s = path.join(src, entry.name);
+    const d = path.join(dest, entry.name);
+    if (entry.isDirectory()) copyDirSync(s, d);
+    else fs.copyFileSync(s, d);
+  }
+}
+
+function readEdges(dbPath) {
+  const db = new Database(dbPath, { readonly: true });
+  const edges = db
+    .prepare(`
+    SELECT n1.name AS src_name, n1.kind AS src_kind, n1.file AS src_file,
+           n2.name AS tgt_name, n2.kind AS tgt_kind, n2.file AS tgt_file,
+           e.kind AS edge_kind, e.confidence
+    FROM edges e
+    JOIN nodes n1 ON e.source_id = n1.id
+    JOIN nodes n2 ON e.target_id = n2.id
+    ORDER BY src_file, src_name, tgt_file, tgt_name, e.kind
+  `)
+    .all();
+  const nodes = db
+    .prepare('SELECT name, kind, file, line FROM nodes ORDER BY name, kind, file, line')
+    .all();
+  db.close();
+  return { edges, nodes };
+}
+
+function edgeKey(e) {
+  return `[${e.edge_kind}] ${e.src_name}(${e.src_kind}@${e.src_file}) -> ${e.tgt_name}(${e.tgt_kind}@${e.tgt_file})`;
+}
+
+describe('Issue #533: incremental edge gap', () => {
+  it('touching leaf file: full vs incremental produce identical edges', async () => {
+    const tmpBase = fs.mkdtempSync(path.join(os.tmpdir(), 'cg-533-'));
+    const fullDir = path.join(tmpBase, 'full');
+    const incrDir = path.join(tmpBase, 'incr');
+    copyDirSync(FIXTURE_DIR, fullDir);
+    copyDirSync(FIXTURE_DIR, incrDir);
+
+    try {
+      // Initial full build on incr copy
+      await buildGraph(incrDir, { incremental: false, skipRegistry: true });
+
+      // Touch the deeply-imported leaf file
+      fs.appendFileSync(path.join(incrDir, 'shared', 'constants.js'), '\n// touched\n');
+      // Incremental rebuild
+      await buildGraph(incrDir, { incremental: true, skipRegistry: true });
+
+      // Full build on full copy (with same change)
+      fs.appendFileSync(path.join(fullDir, 'shared', 'constants.js'), '\n// touched\n');
+      await buildGraph(fullDir, { incremental: false, skipRegistry: true });
+
+      const fullGraph = readEdges(path.join(fullDir, '.codegraph', 'graph.db'));
+      const incrGraph = readEdges(path.join(incrDir, '.codegraph', 'graph.db'));
+
+      // Nodes should match
+      expect(incrGraph.nodes.length).toBe(fullGraph.nodes.length);
+
+      // Detailed edge comparison
+      const fullKeys = new Set(fullGraph.edges.map(edgeKey));
+      const incrKeys = new Set(incrGraph.edges.map(edgeKey));
+      const missing = [...fullKeys].filter((k) => !incrKeys.has(k));
+      const extra = [...incrKeys].filter((k) => !fullKeys.has(k));
+
+      if (missing.length > 0 || extra.length > 0) {
+        console.log(`\nFull build: ${fullGraph.edges.length} edges`);
+        console.log(`Incremental: ${incrGraph.edges.length} edges`);
+        console.log(`\nMissing in incremental (${missing.length}):`);
+        for (const e of missing) console.log(`  - ${e}`);
+        console.log(`\nExtra in incremental (${extra.length}):`);
+        for (const e of extra) console.log(`  + ${e}`);
+      }
+
+      expect(missing).toEqual([]);
+      expect(extra).toEqual([]);
+      expect(incrGraph.edges.length).toBe(fullGraph.edges.length);
+    } finally {
+      fs.rmSync(tmpBase, { recursive: true, force: true });
+    }
+  }, 60_000);
+
+  it('touching mid-level file: full vs incremental produce identical edges', async () => {
+    const tmpBase = fs.mkdtempSync(path.join(os.tmpdir(), 'cg-533b-'));
+    const fullDir = path.join(tmpBase, 'full');
+    const incrDir = path.join(tmpBase, 'incr');
+    copyDirSync(FIXTURE_DIR, fullDir);
+    copyDirSync(FIXTURE_DIR, incrDir);
+
+    try {
+      await buildGraph(incrDir, { incremental: false, skipRegistry: true });
+
+      // Touch a mid-level file (imported by features but imports from shared)
+      fs.appendFileSync(path.join(incrDir, 'shared', 'helpers.js'), '\n// touched\n');
+      await buildGraph(incrDir, { incremental: true, skipRegistry: true });
+
+      fs.appendFileSync(path.join(fullDir, 'shared', 'helpers.js'), '\n// touched\n');
+      await buildGraph(fullDir, { incremental: false, skipRegistry: true });
+
+      const fullGraph = readEdges(path.join(fullDir, '.codegraph', 'graph.db'));
+      const incrGraph = readEdges(path.join(incrDir, '.codegraph', 'graph.db'));
+
+      const fullKeys = new Set(fullGraph.edges.map(edgeKey));
+      const incrKeys = new Set(incrGraph.edges.map(edgeKey));
+      const missing = [...fullKeys].filter((k) => !incrKeys.has(k));
+      const extra = [...incrKeys].filter((k) => !fullKeys.has(k));
+
+      if (missing.length > 0 || extra.length > 0) {
+        console.log(`\nFull: ${fullGraph.edges.length}, Incr: ${incrGraph.edges.length}`);
+        console.log(`Missing (${missing.length}):`);
+        for (const e of missing) console.log(`  - ${e}`);
+        console.log(`Extra (${extra.length}):`);
+        for (const e of extra) console.log(`  + ${e}`);
+      }
+
+      expect(missing).toEqual([]);
+      expect(extra).toEqual([]);
+    } finally {
+      fs.rmSync(tmpBase, { recursive: true, force: true });
+    }
+  }, 60_000);
+});
diff --git a/tests/integration/watcher-rebuild.test.js b/tests/integration/watcher-rebuild.test.js
new file mode 100644
index 000000000..b2f031422
--- /dev/null
+++ b/tests/integration/watcher-rebuild.test.js
@@ -0,0 +1,169 @@
+/**
+ * Watcher rebuild parity test (#533).
+ *
+ * Exercises the `rebuildFile` function (the watcher code path) directly,
+ * verifying that single-file rebuilds with reverse-dep cascade produce
+ * identical nodes and edges to a full build.
+ *
+ * This is distinct from incr-edge-gap.test.js which tests the build
+ * pipeline's incremental path (detect-changes.js).
+ */
+
+import fs from 'node:fs';
+import os from 'node:os';
+import path from 'node:path';
+import Database from 'better-sqlite3';
+import { afterAll, beforeAll, describe, expect, it } from 'vitest';
+import { getNodeId as getNodeIdQuery, initSchema, openDb } from '../../src/db/index.js';
+import { rebuildFile } from '../../src/domain/graph/builder/incremental.js';
+import { buildGraph } from '../../src/domain/graph/builder.js';
+
+const FIXTURE_DIR = path.join(import.meta.dirname, '..', 'fixtures', 'deep-deps-project');
+
+function copyDirSync(src, dest) {
+  fs.mkdirSync(dest, { recursive: true });
+  for (const entry of fs.readdirSync(src, { withFileTypes: true })) {
+    const s = path.join(src, entry.name);
+    const d = path.join(dest, entry.name);
+    if (entry.isDirectory()) copyDirSync(s, d);
+    else fs.copyFileSync(s, d);
+  }
+}
+
+function readGraph(dbPath) {
+  const db = new Database(dbPath, { readonly: true });
+  try {
+    const nodes = db
+      .prepare('SELECT name, kind, file, line FROM nodes ORDER BY name, kind, file, line')
+      .all();
+    const edges = db
+      .prepare(
+        `SELECT n1.name AS src, n1.file AS src_file, n2.name AS tgt, n2.file AS tgt_file, e.kind
+         FROM edges e
+         JOIN nodes n1 ON e.source_id = n1.id
+         JOIN nodes n2 ON e.target_id = n2.id
+         ORDER BY n1.name, n1.file, n2.name, n2.file, e.kind`,
+      )
+      .all();
+    return { nodes, edges };
+  } finally {
+    db.close();
+  }
+}
+
+/** Build the prepared statements object that watcher.js normally provides. */
+function makeStmts(db) {
+  const stmts = {
+    insertNode: db.prepare(
+      'INSERT OR IGNORE INTO nodes (name, kind, file, line, end_line) VALUES (?, ?, ?, ?, ?)',
+    ),
+    getNodeId: {
+      get: (name, kind, file, line) => {
+        const id = getNodeIdQuery(db, name, kind, file, line);
+        return id != null ? { id } : undefined;
+      },
+    },
+    insertEdge: db.prepare(
+      'INSERT INTO edges (source_id, target_id, kind, confidence, dynamic) VALUES (?, ?, ?, ?, ?)',
+    ),
+    deleteNodes: db.prepare('DELETE FROM nodes WHERE file = ?'),
+    deleteEdgesForFile: null,
+    countNodes: db.prepare('SELECT COUNT(*) as c FROM nodes WHERE file = ?'),
+    countEdgesForFile: null,
+    findNodeInFile: db.prepare(
+      "SELECT id, file FROM nodes WHERE name = ? AND kind IN ('function', 'method', 'class', 'interface', 'type', 'struct', 'enum', 'trait', 'record', 'module', 'constant') AND file = ?",
+    ),
+    findNodeByName: db.prepare(
+      "SELECT id, file FROM nodes WHERE name = ? AND kind IN ('function', 'method', 'class', 'interface', 'type', 'struct', 'enum', 'trait', 'record', 'module', 'constant')",
+    ),
+    listSymbols: db.prepare("SELECT name, kind, line FROM nodes WHERE file = ? AND kind != 'file'"),
+  };
+
+  const origDeleteEdges = db.prepare(
+    `DELETE FROM edges WHERE source_id IN (SELECT id FROM nodes WHERE file = @f) OR target_id IN (SELECT id FROM nodes WHERE file = @f)`,
+  );
+  const origCountEdges = db.prepare(
+    `SELECT COUNT(*) as c FROM edges WHERE source_id IN (SELECT id FROM nodes WHERE file = @f) OR target_id IN (SELECT id FROM nodes WHERE file = @f)`,
+  );
+  stmts.deleteEdgesForFile = { run: (f) => origDeleteEdges.run({ f }) };
+  stmts.countEdgesForFile = { get: (f) => origCountEdges.get({ f }) };
+
+  return stmts;
+}
+
+describe('Watcher rebuildFile parity (#533)', () => {
+  let fullDir;
+  let watcherDir;
+  let tmpBase;
+
+  beforeAll(async () => {
+    tmpBase = fs.mkdtempSync(path.join(os.tmpdir(), 'cg-watcher-533-'));
+    fullDir = path.join(tmpBase, 'full');
+    watcherDir = path.join(tmpBase, 'watcher');
+    copyDirSync(FIXTURE_DIR, fullDir);
+    copyDirSync(FIXTURE_DIR, watcherDir);
+
+    // Step 1: Full build both copies
+    await buildGraph(fullDir, { incremental: false, skipRegistry: true });
+    await buildGraph(watcherDir, { incremental: false, skipRegistry: true });
+
+    // Step 2: Touch the leaf file (shared/constants.js) in the watcher copy
+    const leafPath = path.join(watcherDir, 'shared', 'constants.js');
+    fs.appendFileSync(leafPath, '\n// touched\n');
+
+    // Step 3: Use rebuildFile (the watcher code path) to rebuild
+    const dbPath = path.join(watcherDir, '.codegraph', 'graph.db');
+    const db = openDb(dbPath);
+    initSchema(db);
+    const stmts = makeStmts(db);
+    await rebuildFile(db, watcherDir, leafPath, stmts, { engine: 'auto' }, null);
+    db.close();
+
+    // Step 4: Apply same change to full copy and do a full rebuild
+    const fullLeafPath = path.join(fullDir, 'shared', 'constants.js');
+    fs.appendFileSync(fullLeafPath, '\n// touched\n');
+    await buildGraph(fullDir, { incremental: false, skipRegistry: true });
+  }, 60_000);
+
+  afterAll(() => {
+    try {
+      if (tmpBase) fs.rmSync(tmpBase, { recursive: true, force: true });
+    } catch {
+      /* ignore */
+    }
+  });
+
+  it('produces identical node count', () => {
+    const fullGraph = readGraph(path.join(fullDir, '.codegraph', 'graph.db'));
+    const watcherGraph = readGraph(path.join(watcherDir, '.codegraph', 'graph.db'));
+    expect(watcherGraph.nodes.length).toBe(fullGraph.nodes.length);
+  });
+
+  it('produces identical edge count', () => {
+    const fullGraph = readGraph(path.join(fullDir, '.codegraph', 'graph.db'));
+    const watcherGraph = readGraph(path.join(watcherDir, '.codegraph', 'graph.db'));
+
+    if (watcherGraph.edges.length !== fullGraph.edges.length) {
+      const fSet = new Set(fullGraph.edges.map((e) => `${e.src}->${e.tgt}[${e.kind}]`));
+      const wSet = new Set(watcherGraph.edges.map((e) => `${e.src}->${e.tgt}[${e.kind}]`));
+      const missing = [...fSet].filter((k) => !wSet.has(k));
+      const extra = [...wSet].filter((k) => !fSet.has(k));
+      console.log(`Missing in watcher (${missing.length}):`, missing.slice(0, 10));
+      console.log(`Extra in watcher (${extra.length}):`, extra.slice(0, 10));
+    }
+
+    expect(watcherGraph.edges.length).toBe(fullGraph.edges.length);
+  });
+
+  it('produces identical nodes', () => {
+    const fullGraph = readGraph(path.join(fullDir, '.codegraph', 'graph.db'));
+    const watcherGraph = readGraph(path.join(watcherDir, '.codegraph', 'graph.db'));
+    expect(watcherGraph.nodes).toEqual(fullGraph.nodes);
+  });
+
+  it('produces identical edges', () => {
+    const fullGraph = readGraph(path.join(fullDir, '.codegraph', 'graph.db'));
+    const watcherGraph = readGraph(path.join(watcherDir, '.codegraph', 'graph.db'));
+    expect(watcherGraph.edges).toEqual(fullGraph.edges);
+  });
+});