codegraph/docs/SEARCH_QUALITY_LOOP.md

CodeGraph Search Quality Loop

You are testing and improving CodeGraph's search quality for a specific language. The user will give you a real-world codebase path to test against.

What You're Fixing

When an LLM queries CodeGraph via MCP tools (codegraph_search, codegraph_explore, codegraph_callees), the results must be relevant. The main failure mode is: methods with common names (like run, get, handle) flood results and bury the actual target. The fix is usually adding getReceiverType to the language extractor so methods include their owner type in the FTS-indexed qualified_name.

Example: Go's func (sl *scrapeLoop) run() was indexed as scrape.go::scrape.go::run. After adding getReceiverType, it became scrape.go::scrapeLoop::run — now FTS can rank it above unrelated run methods when the query mentions "scrapeLoop".

The Loop

1. Pick a test query

Choose a query that exercises the language's method-on-type pattern. Good queries mention:

• A specific type/class/struct name
• A method on that type
• A broader topic connecting multiple files

Example for Go: "scrapeLoop run scrape lifecycle TSDB storage"

2. Index the codebase

rm -rf <codebase_path>/.codegraph
node dist/bin/codegraph.js init -iv <codebase_path>

The -iv flag gives verbose output showing extraction progress, node/edge counts, and timing.

3. Check what the DB produced

# Does the method have its owner type in qualified_name?
sqlite3 <codebase_path>/.codegraph/codegraph.db \
  "SELECT name, kind, qualified_name FROM nodes WHERE name = '<method>' AND file_path LIKE '%<file>%';"

# GOOD: file.rs::StructName::method_name
# BAD:  file.rs::file.rs::method_name  ← owner type missing, FTS can't find it

4. Test search ranking

node -e "
const { CodeGraph } = require('./dist/index.js');
async function test() {
  const cg = await CodeGraph.open('<codebase_path>');

  // Does the target method rank #1?
  console.log('=== searchNodes ===');
  const results = cg.searchNodes('<OwnerType> <method>', { limit: 10, kinds: ['method'] });
  for (const r of results) {
    console.log(\`\${r.score.toFixed(2)} | \${r.node.name} (\${r.node.kind}) | \${r.node.filePath}:\${r.node.startLine}\`);
  }

  // Does explore find the right file?
  console.log('\n=== findRelevantContext ===');
  const subgraph = await cg.findRelevantContext('<your natural language query>', {
    searchLimit: 8, traversalDepth: 3, maxNodes: 80, minScore: 0.2,
  });
  const fileGroups = new Map();
  for (const node of subgraph.nodes.values()) {
    if (!fileGroups.has(node.filePath)) fileGroups.set(node.filePath, []);
    fileGroups.get(node.filePath).push(node.name);
  }
  console.log('Entry points:');
  for (const rootId of subgraph.roots.slice(0, 8)) {
    const node = subgraph.nodes.get(rootId);
    if (node) console.log(\`  \${node.name} (\${node.kind}) - \${node.filePath}:\${node.startLine}\`);
  }
  console.log('Top files:');
  for (const [file, nodes] of [...fileGroups.entries()].sort((a,b) => b[1].length - a[1].length).slice(0, 5)) {
    console.log(\`  \${file} (\${nodes.length}): \${nodes.slice(0, 5).join(', ')}\`);
  }

  // Does qualified lookup resolve correctly?
  console.log('\n=== qualified lookup ===');
  const qr = cg.searchNodes('<OwnerType>.<method>', { limit: 50 });
  const exact = qr.filter(r => r.node.qualifiedName.includes('<OwnerType>::<method>'));
  console.log(\`\${exact.length} match(es) for <OwnerType>.<method>\`);
  if (exact[0]) {
    const callees = cg.getCallees(exact[0].node.id);
    console.log('Callees:', callees.map(c => c.node.name).join(', '));
  }

  await cg.close();
}
test().catch(console.error);
"

5. If results are bad, diagnose and fix

Symptom	Cause	Fix
Target method not in top 10 of searchNodes	Owner type missing from qualified_name	Add getReceiverType to src/extraction/languages/<lang>.ts
Explore returns irrelevant files	Common method name flooding exact matches	Check co-location boost in src/db/queries.ts: findNodesByExactName
A key term is being dropped from search	It's in the STOP_WORDS list	Edit src/search/query-utils.ts
<OwnerType>.<method> returns "not found"	qualified_name doesn't contain OwnerType::method	Fix getReceiverType output

6. Rebuild and re-test

npm run build
# If you changed extraction (getReceiverType), must re-index:
rm -rf <codebase_path>/.codegraph
node dist/bin/codegraph.js init -iv <codebase_path>
# Then re-run Step 4

7. Run the test suite before finishing

npm test

All 378+ tests must pass.

How to Add getReceiverType for a Language

Only needed for languages where methods are top-level or outside their owner type in the AST. If the language nests methods inside class/struct bodies (Python, Java, TypeScript, C#), the qualified name already includes the parent — verify with Step 3 before adding anything.

1. Add the hook to the language extractor

In src/extraction/languages/<lang>.ts, add getReceiverType to the extractor object:

getReceiverType: (node, source) => {
  // Extract the owner type name from the method's AST node.
  // Return the type name string, or undefined if not applicable.
  // 
  // The core extractMethod() in tree-sitter.ts will use this to set:
  //   qualifiedName = `${filePath}::${receiverType}::${methodName}`
},

2. Reference: Go implementation

// src/extraction/languages/go.ts
getReceiverType: (node, source) => {
  const receiver = getChildByField(node, 'receiver');
  if (!receiver) return undefined;
  const text = getNodeText(receiver, source);
  const match = text.match(/\*?\s*([A-Za-z_][A-Za-z0-9_]*)\s*\)/);
  return match?.[1];
},

3. Where it's consumed

src/extraction/tree-sitter.ts in extractMethod():

const receiverType = this.extractor.getReceiverType?.(node, this.source);
if (receiverType) {
  extraProps.qualifiedName = `${this.filePath}::${receiverType}::${name}`;
}

Key Files

File	Role
src/extraction/languages/<lang>.ts	Language extractor — implement getReceiverType here
src/extraction/tree-sitter.ts	Core extraction — extractMethod() uses the hook
src/extraction/tree-sitter-types.ts	LanguageExtractor interface definition
src/search/query-utils.ts	STOP_WORDS, extractSearchTerms, scorePathRelevance
src/db/queries.ts	searchNodesFTS (BM25), findNodesByExactName (co-location)
src/context/index.ts	findRelevantContext — hybrid search + co-location boost
src/mcp/tools.ts	MCP handlers — matchesSymbol uses qualifiedName.includes("Type::method")

Languages Completed

• Go — getReceiverType extracts receiver from func (sl *Type) method()

Languages To Do

Check these — only add getReceiverType if methods are top-level (not nested inside their owner type in the AST):

• Rust — methods in impl Type { } blocks
• C++ — out-of-class method definitions Type::method()
• Swift — methods in extension Type { } blocks
• Kotlin — extension functions fun Type.method()

Verify these DON'T need it (methods nested in class body → qualified name should already be correct):

• Python — verify qualified_name includes class name
• Java — verify qualified_name includes class name
• TypeScript — verify qualified_name includes class name
• C# — verify qualified_name includes class name