Method extractNodeCode

src/context/index.ts:1163–1191

* Extract code from a node's source file

(node: Node)

   * Extract code from a node's source file
   */
  private async extractNodeCode(node: Node): Promise<string | null> {
    // SECURITY (#383): a config-leaf node's on-disk line is `key = <secret>`.
    // Return the KEY only — never read the value off disk. This closes the
    // includeCode / buildContext code-block path, mirroring the explore source
    // renderer; an agent that genuinely needs a value can read the file itself.
    if (isConfigLeafNode(node)) {
      return node.signature || node.qualifiedName || node.name;
    }

    const filePath = validatePathWithinRoot(this.projectRoot, node.filePath);

    if (!filePath || !fs.existsSync(filePath)) {
      return null;
    }

    try {
      const content = fs.readFileSync(filePath, 'utf-8');
      const lines = content.split('\n');

      // Extract lines (1-indexed to 0-indexed)
      const startIdx = Math.max(0, node.startLine - 1);
      const endIdx = Math.min(lines.length, node.endLine);

      return lines.slice(startIdx, endIdx).join('\n');
    } catch (error) {
      logDebug('Failed to extract code from node', { nodeId: node.id, filePath: node.filePath, error: String(error) });
      return null;
    }
  }

  /**
   * Get entry points from a subgraph (the root nodes)