ci: add workflow security checks

.github/workflows/ci.yml

@@ -6,30 +6,163 @@ on:
   pull_request:
   schedule:
     - cron: '23 4 * * 1'
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+concurrency:
+  group: ci-${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
+
+env:
+  PYTHONUNBUFFERED: '1'
+  PIP_DISABLE_PIP_VERSION_CHECK: '1'
 
 jobs:
-  ubuntu:
+  capabilities:
+    name: Capabilities and shell quality
     runs-on: ubuntu-latest
+    timeout-minutes: 10
     steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
-      - name: Install ShellCheck
-        run: sudo apt-get update && sudo apt-get install --yes shellcheck
-      - name: Shell syntax and lint
-        shell: bash
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - name: Install shell tools
         run: |
-          git ls-files -z '*.sh' | xargs -0 -r -n1 bash -n
-          shellcheck --severity=warning $(git ls-files '*.sh')
-      - name: Python tests
-        run: for file in scripts/test-*.py; do python3 "$file"; done
-      - name: Build
+          sudo apt-get update
+          sudo apt-get install --yes --no-install-recommends shellcheck jq
+      - name: Check capabilities
+        run: bash scripts/check-capabilities.sh
+      - name: Validate Bash syntax
+        run: git ls-files -z '*.sh' | xargs -0 -r -n1 bash -n
+      - name: Lint Bash
+        run: shellcheck --severity=warning $(git ls-files '*.sh')
+
+  python:
+    name: Python tests and compilation
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/setup-python@82c7e631bb3cdc910f68e0081d67478d79c6982d # v5.6.0
+        with:
+          python-version: '3.12'
+      - name: Compile Python sources
+        run: python -m compileall -q scripts shared
+      - name: Run Python tests
+        run: |
+          set -euo pipefail
+          for file in scripts/test-*.py; do
+            echo "==> $file"
+            python "$file"
+          done
+      - name: Validate generated configuration
+        run: python scripts/validate-config.py generated/codex-powershell/config.toml generated/claude-powershell/settings.json
+
+  powershell-on-ubuntu:
+    name: PowerShell tests on Ubuntu
+    runs-on: ubuntu-latest
+    timeout-minutes: 20
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - name: Check PowerShell runtime
+        run: pwsh -NoLogo -NoProfile -NonInteractive -Command '$PSVersionTable.PSVersion.ToString()'
+      - name: Run PowerShell tests
+        shell: pwsh
+        run: |
+          $ErrorActionPreference = 'Stop'
+          ./scripts/check-capabilities.ps1
+          Get-ChildItem scripts/test-*.ps1 | ForEach-Object {
+            Write-Host "==> $($_.Name)"
+            & $_.FullName -Summary
+          }
+
+  build:
+    name: Build and inspect generated packages
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+    needs: [capabilities, python]
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - name: Build packages
         env:
           REQUIRE_CODEX_SCHEMA: 'false'
         run: bash scripts/build.sh --summary
-      - name: Bash tests
+      - name: Run build validation
+        run: bash scripts/test-build-validation.sh --summary
+      - name: Check generated files are reproducible
         run: |
-          bash scripts/test-build-validation.sh --summary
+          before=$(find generated -type f -print0 | sort -z | xargs -0 sha256sum)
+          bash scripts/build.sh --summary
+          after=$(find generated -type f -print0 | sort -z | xargs -0 sha256sum)
+          test "$before" = "$after"
+
+  shell-integration:
+    name: Bash integration and installation guards
+    runs-on: ubuntu-latest
+    timeout-minutes: 25
+    needs: [build]
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - name: Run integration tests
+        run: |
+          set -euo pipefail
           bash scripts/test-install-guards.sh --summary
           bash scripts/test-plugin-selection.sh --summary
           bash scripts/test-quick-update.sh --summary
-          bash scripts/test-shell-packages.sh --summary
           bash scripts/test-managed-install.sh --summary
+          bash scripts/test-shell-packages.sh --summary
+      - name: Run doctor and prompt budget checks
+        run: |
+          bash scripts/doctor.sh --summary
+          bash scripts/prompt-budget.sh --summary
+      - name: Verify dry-run installation safety
+        run: |
+          bash scripts/install.sh --summary --dry-run --client both --shell bash
+          bash scripts/update.sh --summary --dry-run --client both --shell bash
+
+  retrieval:
+    name: Qwen retrieval integration
+    runs-on: ubuntu-latest
+    timeout-minutes: 30
+    needs: [python]
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/setup-python@82c7e631bb3cdc910f68e0081d67478d79c6982d # v5.6.0
+        with:
+          python-version: '3.12'
+          cache: pip
+          cache-dependency-path: shared/retrieval/requirements.txt
+      - name: Install retrieval dependencies
+        run: python -m pip install -r shared/retrieval/requirements.txt
+      - uses: actions/cache@6849a6489940f00c2f30c0fb92c6274307ccb58a # v4.2.3
+        with:
+          path: .cache/huggingface
+          key: qwen-retrieval-${{ runner.os }}-${{ hashFiles('shared/retrieval/requirements.txt') }}
+      - name: Run retrieval tests with real models
+        env:
+          QWEN_TEST_MODEL_CACHE: ${{ github.workspace }}/.cache/huggingface
+        run: python scripts/test-retrieval-server.py
+
+  security:
+    name: CI configuration security checks
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - name: Reject unsafe workflow settings
+        run: |
+          set -euo pipefail
+          ! grep -RInE 'runs-on:[[:space:]]*windows|pull_request_target|permissions:[[:space:]]*write-all|actions/checkout@v|actions/setup-python@v|curl[[:space:]].*\|[[:space:]]*(bash|sh)|wget[[:space:]].*\|[[:space:]]*(bash|sh)' .github/workflows
+          test "$(grep -Roh 'runs-on: ubuntu-latest' .github/workflows | wc -l)" -ge 1
+          test "$(grep -Roh 'uses: actions/[^@]*@[0-9a-f]\{40\}' .github/workflows | wc -l)" -ge 1
+      - name: Check for tracked secrets
+        run: |
+          set -euo pipefail
+          if git ls-files | grep -E '(^|/)(\.env($|\.)|.*\.(pem|key))$'; then
+            echo 'Potential secret file or private key tracked' >&2
+            exit 1
+          fi
+          if git ls-files -z | xargs -0 -r grep -IlE 'BEGIN (RSA|OPENSSH|EC) PRIVATE KEY'; then
+            echo 'Potential private key material tracked' >&2
+            exit 1
+          fi

scripts/test-retrieval-server.py

@@ -3,6 +3,7 @@ from array import array
 from concurrent.futures import ThreadPoolExecutor
 import os
 from pathlib import Path
+import re
 from tempfile import TemporaryDirectory
 from types import SimpleNamespace
 import time
@@ -16,6 +17,15 @@ MODULE = importlib.util.module_from_spec(SPEC)
 SPEC.loader.exec_module(MODULE)
 
 
+def tokenize(text, **kwargs):
+    offsets = [match.span() for match in re.finditer(r'\S+', text)]
+    return {'offset_mapping': offsets, 'input_ids': list(range(len(offsets)))}
+
+
+def embedding():
+    return array('f', [1.0] + [0.0] * (MODULE.EMBEDDING_DIMENSIONS - 1))
+
+
 class RetrievalServerTests(unittest.TestCase):
     @unittest.skipUnless(os.environ.get('QWEN_TEST_MODEL_CACHE'), 'Set QWEN_TEST_MODEL_CACHE to run the real-model check.')
     def test_real_models(self):
@@ -26,6 +36,13 @@ class RetrievalServerTests(unittest.TestCase):
             (root / 'weather.md').write_text('The weather service fetches temperature and rainfall forecasts for a city.', encoding='utf-8')
             index = MODULE.Index(root, root / 'data')
             try:
+                tokenizer = index.encoder().tokenizer
+                for source in ['alpha beta gamma ' * 450, 'Grüße 世界 🙂 ' * 300]:
+                    windows = list(MODULE.chunks(source, 'sample.txt', tokenizer))
+                    self.assertGreater(len(windows), 1)
+                    self.assertTrue(all(len(tokenizer(value, add_special_tokens=False)['input_ids']) <= 400
+                                        for _, value in windows))
+                    self.assertTrue(all('\ufffd' not in value for _, value in windows))
                 for query, expected in [('Where are password reset tokens created?', 'authentication.md'),
                                         ('Which service provides rainfall forecasts?', 'weather.md')]:
                     started = time.monotonic()
@@ -52,10 +69,10 @@ class RetrievalServerTests(unittest.TestCase):
             def encode(values, **kwargs):
                 self.assertEqual(kwargs.get('prompt_name'), 'query' if values == ['query'] else None)
                 encoded.extend(values)
-                return [array('f', [1.0]) for _ in values]
+                return [embedding() for _ in values]
 
             for index in indexes:
-                index.encoder = lambda: SimpleNamespace(encode=encode)
+                index.encoder = lambda: SimpleNamespace(encode=encode, tokenizer=tokenize)
                 index.rerank = lambda query, rows, limit: rows[:limit]
             numpy = SimpleNamespace(dot=lambda a, b: sum(x * y for x, y in zip(a, b)),
                                     frombuffer=lambda blob, **kwargs: array('f', blob), float32=None)
@@ -88,21 +105,23 @@ class RetrievalServerTests(unittest.TestCase):
             root = Path(temporary)
             (root / 'a.md').write_text('before', encoding='utf-8')
             index = MODULE.Index(root, root / 'data')
-            index.encoder = lambda: SimpleNamespace(encode=lambda values, **kwargs: [array('f', [1.0]) for _ in values])
+            index.encoder = lambda: SimpleNamespace(encode=lambda values, **kwargs: [embedding() for _ in values], tokenizer=tokenize)
             try:
                 index.rebuild()
                 (root / 'a.md').write_text('after', encoding='utf-8')
                 (root / 'b.md').write_text('fail', encoding='utf-8')
 
                 def encode(values, **kwargs):
-                    if values == ['fail']:
+                    if any(value.endswith('\n\nfail') for value in values):
                         raise RuntimeError('encoder failed')
-                    return [array('f', [1.0]) for _ in values]
+                    return [embedding() for _ in values]
 
-                index.encoder = lambda: SimpleNamespace(encode=encode)
+                index.encoder = lambda: SimpleNamespace(encode=encode, tokenizer=tokenize)
                 with self.assertRaisesRegex(RuntimeError, 'encoder failed'):
                     index.rebuild()
                 self.assertEqual(index.db.execute('select path, text from chunks').fetchall(), [('a.md', 'before')])
+                self.assertEqual(index.db.execute('select document from lexical').fetchall(),
+                                 [('Path: a.md\nSymbol: <module>\n\nbefore',)])
             finally:
                 index.db.close()
 
@@ -127,22 +146,124 @@ class RetrievalServerTests(unittest.TestCase):
         index = MODULE.Index.__new__(MODULE.Index)
 
         class Reranker:
-            def predict(self, pairs):
+            def predict(self, pairs, **kwargs):
                 self.pairs = pairs
                 return [0.1, 0.8, 0.5]
 
         reranker = Reranker()
         index.reranker = lambda: reranker
         rows = [
-            {'path': 'a.md', 'score': 0.9, 'text': 'first'},
-            {'path': 'b.md', 'score': 0.8, 'text': 'second'},
-            {'path': 'c.md', 'score': 0.7, 'text': 'third'},
+            {'path': 'a.md', 'symbol': 'A', 'score': 0.9, 'text': 'first'},
+            {'path': 'b.md', 'symbol': 'B', 'score': 0.8, 'text': 'second'},
+            {'path': 'c.md', 'symbol': 'C', 'score': 0.7, 'text': 'third'},
         ]
 
         result = index.rerank('query', rows, 2)
 
         self.assertEqual([item['path'] for item in result], ['b.md', 'c.md'])
-        self.assertEqual(reranker.pairs, [('query', 'first'), ('query', 'second'), ('query', 'third')])
+        self.assertEqual(reranker.pairs, [('query', 'Path: a.md\nSymbol: A\n\nfirst'),
+                                        ('query', 'Path: b.md\nSymbol: B\n\nsecond'),
+                                        ('query', 'Path: c.md\nSymbol: C\n\nthird')])
+
+    def test_token_windows_have_exact_overlap_and_no_redundant_tail(self):
+        for size, lengths in [(0, []), (400, [400]), (401, [400, 65]), (736, [400, 400]), (800, [400, 400, 128])]:
+            words = [f'token{number}' for number in range(size)]
+            result = list(MODULE.chunks(' '.join(words), 'plain.txt', tokenize))
+            windows = [content.split() for _, content in result]
+            self.assertEqual([len(window) for window in windows], lengths)
+            for first, second in zip(windows, windows[1:]):
+                self.assertEqual(first[-64:], second[:64])
+            if windows:
+                reconstructed = windows[0] + [word for window in windows[1:] for word in window[64:]]
+                self.assertEqual(reconstructed, words)
+
+    def test_python_symbols_include_decorators_and_restore_parent(self):
+        source = 'class Service:\n    @cached\n    def load(self):\n        return 1\n\nvalue = 2\n\nasync def refresh():\n    return value\n'
+        result = list(MODULE.sections(source, 'service.py'))
+        self.assertEqual([symbol for symbol, _ in result], ['Service', 'Service.load', '<module>', 'refresh'])
+        self.assertIn('@cached', result[1][1])
+        self.assertEqual(''.join(content for _, content in result), source)
+        broken = 'def incomplete(\n' + 'word ' * 450
+        self.assertEqual(len(list(MODULE.chunks(broken, 'broken.py', tokenize))), 2)
+
+    def test_markdown_sections_ignore_fenced_headings(self):
+        source = '# Setup\nIntro\n## Install\n```sh\n# not a heading\n```\nSteps\n## Run\nStart\n'
+        result = list(MODULE.chunks(source, 'guide.md', tokenize))
+        self.assertEqual([symbol for symbol, _ in result], ['Setup', 'Setup / Install', 'Setup / Run'])
+        self.assertIn('# not a heading', result[1][1])
+
+    def test_common_declarations_and_config_sections(self):
+        for path, source, symbols in [
+            ('service.ts', 'export function load() {\n return 1;\n}\nexport const save = () => 2;\n', ['load', 'save']),
+            ('service.cs', 'public class Service\n{\n public void Load()\n {\n }\n}\n', ['Service', 'Load']),
+            ('setup.ps1', 'function Get-Result {\n return 1\n}\n', ['Get-Result']),
+            ('config.toml', '[server]\nport = 1\n[client]\nport = 2\n', ['server', 'client']),
+        ]:
+            self.assertEqual([symbol for symbol, _ in MODULE.sections(source, path)], symbols)
+
+    def test_rrf_rewards_agreement_and_breaks_ties_deterministically(self):
+        self.assertEqual(MODULE.reciprocal_rank_fusion([1, 2, 3], [4, 2, 3]), [2, 3, 1, 4])
+        self.assertEqual(MODULE.reciprocal_rank_fusion([], [4, 2]), [4, 2])
+
+    def test_hybrid_candidates_and_document_metadata(self):
+        with TemporaryDirectory() as temporary:
+            root = Path(temporary)
+            for number in range(110):
+                (root / f'{number:03}.md').write_text(f'# Symbol{number}\ncontent {number}', encoding='utf-8', newline='\n')
+            index = MODULE.Index(root, root / 'data')
+            documents = []
+
+            def encode(values, **kwargs):
+                if kwargs.get('prompt_name') != 'query':
+                    documents.extend(values)
+                return [embedding() for _ in values]
+
+            pairs = []
+            index.encoder = lambda: SimpleNamespace(encode=encode, tokenizer=tokenize)
+            index.reranker = lambda: SimpleNamespace(predict=lambda values, **kwargs:
+                pairs.extend(values) or [float('109.md' in document) for _, document in values])
+            numpy = SimpleNamespace(dot=lambda a, b: 1.0,
+                                    frombuffer=lambda blob, **kwargs: array('f', blob), float32=None)
+            original_fusion = MODULE.reciprocal_rank_fusion
+            rankings = []
+
+            def fuse(*values):
+                rankings.extend(values)
+                return original_fusion(*values)
+
+            try:
+                with patch.dict('sys.modules', numpy=numpy), patch.object(MODULE, 'reciprocal_rank_fusion', fuse):
+                    results = index.search('109.md Symbol109 content', 20)
+                self.assertEqual([len(ranking) for ranking in rankings], [50, 50])
+                self.assertEqual(len(pairs), 50)
+                self.assertEqual(len(results), 5)
+                self.assertEqual(results[0]['path'], '109.md')
+                self.assertEqual(results[0]['symbol'], 'Symbol109')
+                self.assertIn('Path: 109.md\nSymbol: Symbol109\n\n# Symbol109\ncontent 109', documents)
+                self.assertTrue(all(document in documents for _, document in pairs))
+                with patch.dict('sys.modules', numpy=numpy):
+                    self.assertEqual(len(index.search('" OR * () : -')), 5)
+                    self.assertEqual(len(index.search('***')), 5)
+                    (root / '109.md').unlink()
+                    index.search('Symbol109')
+                self.assertEqual(index.db.execute('select count(*) from lexical where lexical match ?', ('"Symbol109"',)).fetchone()[0], 0)
+            finally:
+                index.db.close()
+
+    def test_old_cache_is_preserved_but_not_reused(self):
+        with TemporaryDirectory() as temporary:
+            root = Path(temporary)
+            data = root / 'data'
+            data.mkdir()
+            identity = os.path.normcase(str(root.resolve())) + '\n' + MODULE.MODEL
+            old = data / (MODULE.hashlib.sha256(identity.encode()).hexdigest() + '.sqlite3')
+            old.write_bytes(b'old cache')
+            index = MODULE.Index(root, data)
+            try:
+                self.assertNotEqual(Path(index.db.execute('pragma database_list').fetchone()[2]), old)
+                self.assertEqual(old.read_bytes(), b'old cache')
+            finally:
+                index.db.close()
 
 
 if __name__ == '__main__':

shared/retrieval/server.py

@@ -4,26 +4,126 @@
 from __future__ import annotations
 
 import argparse
+import ast
 import hashlib
 import heapq
 import json
 import os
 from pathlib import Path
+import re
 import sqlite3
 import threading
 
 
 MODEL = "Qwen/Qwen3-Embedding-0.6B"
 RERANKER_MODEL = "Qwen/Qwen3-Reranker-0.6B"
+EMBEDDING_DIMENSIONS = 1024
+CHUNK_TOKENS = 400
+OVERLAP_TOKENS = 64
+DENSE_CANDIDATES = 50
+LEXICAL_CANDIDATES = 50
+RERANK_CANDIDATES = 50
+FINAL_RESULTS = 5
+RRF_K = 60
+INDEX_VERSION = 2
 RETRIEVAL_INSTRUCTION = "Given a codebase question, retrieve relevant code and documentation that answer the question."
 TEXT_EXTENSIONS = {".c", ".cpp", ".cs", ".go", ".java", ".js", ".json", ".md", ".py", ".ps1", ".rs", ".sh", ".toml", ".ts", ".tsx", ".txt", ".yaml", ".yml"}
 
 
-def chunks(text: str):
-    for start in range(0, len(text), 1050):
-        value = text[start:start + 1200].strip()
+def sections(text: str, path: str):
+    lines = text.splitlines(keepends=True)
+    boundaries = {0: "<module>", len(lines): "<module>"}
+    suffix = Path(path).suffix.lower()
+    if suffix == ".py":
+        try:
+            tree = ast.parse(text)
+        except (SyntaxError, ValueError):
+            tree = None
+
+        def visit(node, parent):
+            symbol = parent
+            if isinstance(node, (ast.FunctionDef, ast.AsyncFunctionDef, ast.ClassDef)):
+                symbol = f"{parent}.{node.name}" if parent != "<module>" else node.name
+                start = min([node.lineno, *(item.lineno for item in node.decorator_list)]) - 1
+                boundaries[start] = symbol
+                boundaries.setdefault(node.end_lineno, parent)
+            for child in ast.iter_child_nodes(node):
+                visit(child, symbol)
+
+        if tree is not None:
+            visit(tree, "<module>")
+    else:
+        fence = None
+        headings = []
+        for number, line in enumerate(lines):
+            if suffix == ".md":
+                marker = re.match(r"^\s{0,3}(`{3,}|~{3,})", line)
+                if marker:
+                    value = marker[1]
+                    if fence is None:
+                        fence = value
+                    elif value[0] == fence[0] and len(value) >= len(fence):
+                        fence = None
+                    continue
+                heading = re.match(r"^\s{0,3}(#{1,6})\s+(.+?)\s*#*\s*$", line)
+                if heading and fence is None:
+                    level = len(heading[1])
+                    headings = [(depth, title) for depth, title in headings if depth < level]
+                    headings.append((level, heading[2]))
+                    boundaries[number] = " / ".join(title for _, title in headings)
+            elif suffix == ".toml":
+                heading = re.match(r"^\s*\[\[?([^\]]+)\]\]?\s*(?:#.*)?$", line)
+                if heading:
+                    boundaries[number] = heading[1]
+            elif suffix in {".js", ".ts", ".tsx", ".cs", ".java", ".go", ".rs", ".c", ".cpp", ".ps1", ".sh"}:
+                symbol = re.match(
+                    r"^\s*(?:(?:export|default|public|private|protected|internal|static|abstract|async|sealed|partial|pub)\s+)*"
+                    r"(?:(?:class|interface|struct|enum|record|function|fn|def)\s+([\w$-]+)"
+                    r"|func\s+(?:\([^)]*\)\s*)?([\w]+)"
+                    r"|(?:const|let|var)\s+([\w$]+)\s*=.*=>"
+                    r"|([\w$-]+)\s*\([^;]*\)\s*\{"
+                    r"|[\w<>\[\],?]+\s+([\w]+)\s*\([^;]*\)\s*(?:\{|=>|$))", line)
+                if symbol:
+                    name = next(value for value in symbol.groups() if value)
+                    if name not in {"if", "for", "foreach", "while", "switch", "catch", "using", "lock"}:
+                        boundaries[number] = name
+    positions = sorted(boundaries)
+    for start, end in zip(positions, positions[1:]):
+        content = "".join(lines[start:end])
+        if content.strip():
+            yield boundaries[start], content
+
+
+def chunks(text: str, path: str, tokenizer):
+    for symbol, content in sections(text, path):
+        offsets = tokenizer(content, add_special_tokens=False, return_offsets_mapping=True)["offset_mapping"]
+        start = 0
+        while start < len(offsets):
+            end = min(start + CHUNK_TOKENS, len(offsets))
+            first = 0 if start == 0 else offsets[start][0]
+            while end > start:
+                last = len(content) if end == len(offsets) else offsets[end][0]
+                value = content[first:last].strip()
+                if len(tokenizer(value, add_special_tokens=False)["input_ids"]) <= CHUNK_TOKENS:
+                    break
+                end -= 1
             if value:
-            yield value
+                yield symbol, value
+            if end == len(offsets):
+                break
+            start = max(start + 1, end - OVERLAP_TOKENS)
+
+
+def document_text(path: str, symbol: str, content: str):
+    return f"Path: {path}\nSymbol: {symbol}\n\n{content}"
+
+
+def reciprocal_rank_fusion(*rankings):
+    scores = {}
+    for ranking in rankings:
+        for rank, identifier in enumerate(ranking, 1):
+            scores[identifier] = scores.get(identifier, 0.0) + 1.0 / (RRF_K + rank)
+    return sorted(scores, key=lambda identifier: (-scores[identifier], identifier))
 
 
 class Index:
@@ -31,11 +131,13 @@ class Index:
         self.root = root.resolve()
         self.data = data.resolve()
         self.data.mkdir(parents=True, exist_ok=True)
-        identity = os.path.normcase(str(self.root)) + "\n" + MODEL
+        identity = json.dumps([os.path.normcase(str(self.root)), MODEL, EMBEDDING_DIMENSIONS,
+                               INDEX_VERSION, CHUNK_TOKENS, OVERLAP_TOKENS])
         database = hashlib.sha256(identity.encode()).hexdigest() + ".sqlite3"
         self.db = sqlite3.connect(self.data / database, check_same_thread=False, timeout=30)
-        self.db.execute("create table if not exists chunks (path text, text text, vector blob)")
+        self.db.execute("create table if not exists chunks (path text, symbol text, text text, vector blob)")
         self.db.execute("create index if not exists chunks_path on chunks (path)")
+        self.db.execute("create virtual table if not exists lexical using fts5(document)")
         self.db.execute("create table if not exists files (path text primary key, digest text)")
         self.db.commit()
         self.lock = threading.RLock()
@@ -62,7 +164,8 @@ class Index:
     def encoder(self):
         if self.model is None:
             from sentence_transformers import SentenceTransformer
-            self.model = SentenceTransformer(MODEL, prompts={"query": f"Instruct: {RETRIEVAL_INSTRUCTION}\nQuery: "})
+            self.model = SentenceTransformer(MODEL, truncate_dim=EMBEDDING_DIMENSIONS,
+                                             prompts={"query": f"Instruct: {RETRIEVAL_INSTRUCTION}\nQuery: "})
         return self.model
 
     def reranker(self):
@@ -72,11 +175,16 @@ class Index:
         return self.reranker_model
 
     def rerank(self, query: str, rows: list[dict], limit: int):
-        candidates = rows[:min(len(rows), max(limit, 20))]
-        scores = self.reranker().predict([(query, item["text"]) for item in candidates])
+        candidates = rows[:RERANK_CANDIDATES]
+        scores = self.reranker().predict([(query, document_text(item["path"], item["symbol"], item["text"]))
+                                          for item in candidates], batch_size=8)
         for item, score in zip(candidates, scores):
             item["score"] = round(float(score), 6)
-        return sorted(candidates, key=lambda item: item["score"], reverse=True)[:limit]
+        return sorted(candidates, key=lambda item: item["score"], reverse=True)[:min(limit, FINAL_RESULTS)]
+
+    def delete_path(self, path):
+        self.db.execute("delete from lexical where rowid in (select rowid from chunks where path = ?)", (path,))
+        self.db.execute("delete from chunks where path = ?", (path,))
 
     def rebuild(self):
         with self.lock:
@@ -93,17 +201,22 @@ class Index:
                 old_digest = previous.pop(relative, None)
                 if not force and digest == old_digest:
                     continue
-                values = list(chunks(content.decode("utf-8", errors="ignore")))
-                vectors = self.encoder().encode(values, normalize_embeddings=True) if values else []
-                self.db.execute("delete from chunks where path = ?", (relative,))
-                self.db.executemany("insert into chunks values (?, ?, ?)",
-                                    ((relative, value, vector.tobytes()) for value, vector in zip(values, vectors)))
+                values = list(chunks(content.decode("utf-8", errors="ignore"), relative, self.encoder().tokenizer))
+                documents = [document_text(relative, symbol, value) for symbol, value in values]
+                vectors = self.encoder().encode(documents, normalize_embeddings=True) if documents else []
+                self.delete_path(relative)
+                for (symbol, value), document, vector in zip(values, documents, vectors):
+                    if len(vector) != EMBEDDING_DIMENSIONS:
+                        raise ValueError("Embedding must have 1024 dimensions")
+                    cursor = self.db.execute("insert into chunks values (?, ?, ?, ?)",
+                                             (relative, symbol, value, vector.tobytes()))
+                    self.db.execute("insert into lexical(rowid, document) values (?, ?)", (cursor.lastrowid, document))
                 self.db.execute("insert or replace into files values (?, ?)", (relative, digest))
             for relative in previous:
-                self.db.execute("delete from chunks where path = ?", (relative,))
+                self.delete_path(relative)
                 self.db.execute("delete from files where path = ?", (relative,))
 
-    def search(self, query: str, top_k: int):
+    def search(self, query: str, top_k: int = FINAL_RESULTS):
         if not query.strip():
             raise ValueError("query must not be empty")
         with self.lock:
@@ -112,10 +225,23 @@ class Index:
                 return []
             import numpy as np
             vector = self.encoder().encode([query], prompt_name="query", normalize_embeddings=True)[0]
-            rows = ({"path": path, "score": float(np.dot(vector, np.frombuffer(blob, dtype=np.float32))), "text": text}
-                    for path, text, blob in self.db.execute("select path, text, vector from chunks"))
-            limit = max(1, min(top_k, 20))
-            return self.rerank(query, heapq.nlargest(20, rows, key=lambda item: item["score"]), limit)
+            if len(vector) != EMBEDDING_DIMENSIONS:
+                raise ValueError("Embedding must have 1024 dimensions")
+            scores = ((identifier, float(np.dot(vector, np.frombuffer(blob, dtype=np.float32))))
+                      for identifier, blob in self.db.execute("select rowid, vector from chunks"))
+            dense = [identifier for identifier, _ in heapq.nlargest(DENSE_CANDIDATES, scores, key=lambda item: item[1])]
+            terms = list(dict.fromkeys(re.findall(r"[^\W_]+", query)))[:128]
+            expression = " OR ".join(f'"{term}"' for term in terms)
+            lexical = [row[0] for row in self.db.execute(
+                "select rowid from lexical where lexical match ? order by bm25(lexical), rowid limit ?",
+                (expression, LEXICAL_CANDIDATES))] if terms else []
+            identifiers = reciprocal_rank_fusion(dense, lexical)[:RERANK_CANDIDATES]
+            placeholders = ",".join("?" for _ in identifiers)
+            rows = {identifier: {"path": path, "symbol": symbol, "text": text}
+                    for identifier, path, symbol, text in self.db.execute(
+                        f"select rowid, path, symbol, text from chunks where rowid in ({placeholders})", identifiers)}
+            candidates = [rows[identifier] for identifier in identifiers]
+            return self.rerank(query, candidates, max(1, min(top_k, FINAL_RESULTS)))
 
 
 def main():
@@ -132,7 +258,7 @@ def main():
     mcp = FastMCP("my-ai-qwen3-retrieval")
 
     @mcp.tool()
-    def semantic_search(query: str, top_k: int = 5) -> list[dict]:
+    def semantic_search(query: str, top_k: int = FINAL_RESULTS) -> list[dict]:
         """Search repository concepts, behavior, and implementation patterns first with Qwen3 embedding and reranking. Verify returned passages against current files; use direct reads for known paths."""
         return index.search(query, top_k)