diff --git a/src/analyzers/base.py b/src/analyzers/base.py
new file mode 100644
index 0000000..81d298d
--- /dev/null
+++ b/src/analyzers/base.py
@@ -0,0 +1,129 @@
+"""Base analyzer class and common functionality."""
+
+from abc import ABC, abstractmethod
+from dataclasses import dataclass, field
+from enum import Enum
+from pathlib import Path
+from typing import Optional
+import tree_sitter
+
+
+class SeverityLevel(str, Enum):
+    """Severity levels for findings."""
+
+    CRITICAL = "critical"
+    HIGH = "high"
+    MEDIUM = "medium"
+    LOW = "low"
+
+
+class FindingCategory(str, Enum):
+    """Categories of findings."""
+
+    SECURITY = "security"
+    ANTIPATTERN = "antipattern"
+    SECRET = "secret"
+    PERFORMANCE = "performance"
+
+
+@dataclass
+class Finding:
+    """Represents a code issue finding."""
+
+    rule_id: str
+    rule_name: str
+    severity: SeverityLevel
+    category: FindingCategory
+    message: str
+    suggestion: str
+    file_path: Path
+    line_number: int
+    column: int
+    end_line: Optional[int] = None
+    end_column: Optional[int] = None
+    node: Optional[tree_sitter.Node] = None
+
+    def to_dict(self) -> dict:
+        return {
+            "rule_id": self.rule_id,
+            "rule_name": self.rule_name,
+            "severity": self.severity.value,
+            "category": self.category.value,
+            "message": self.message,
+            "suggestion": self.suggestion,
+            "file_path": str(self.file_path),
+            "line_number": self.line_number,
+            "column": self.column,
+            "end_line": self.end_line,
+            "end_column": self.end_column,
+        }
+
+
+@dataclass
+class AnalysisResult:
+    """Result of analyzing a file."""
+
+    file_path: Path
+    findings: list[Finding] = field(default_factory=list)
+    error: Optional[str] = None
+    lines_of_code: int = 0
+
+    def has_issues(self) -> bool:
+        return len(self.findings) > 0
+
+    def critical_count(self) -> int:
+        return sum(1 for f in self.findings if f.severity == SeverityLevel.CRITICAL)
+
+    def high_count(self) -> int:
+        return sum(1 for f in self.findings if f.severity == SeverityLevel.HIGH)
+
+    def medium_count(self) -> int:
+        return sum(1 for f in self.findings if f.severity == SeverityLevel.MEDIUM)
+
+    def low_count(self) -> int:
+        return sum(1 for f in self.findings if f.severity == SeverityLevel.LOW)
+
+    def summary(self) -> dict:
+        return {
+            "critical": self.critical_count(),
+            "high": self.high_count(),
+            "medium": self.medium_count(),
+            "low": self.low_count(),
+            "total": len(self.findings),
+            "lines_of_code": self.lines_of_code,
+        }
+
+
+class Analyzer(ABC):
+    """Abstract base class for analyzers."""
+
+    @abstractmethod
+    def analyze(
+        self, source_code: str, file_path: Path, tree: tree_sitter.Tree
+    ) -> list[Finding]:
+        """Analyze source code and return findings."""
+        pass
+
+    @abstractmethod
+    def rule_id(self) -> str:
+        """Return unique identifier for the rule."""
+        pass
+
+    @abstractmethod
+    def rule_name(self) -> str:
+        """Return human-readable rule name."""
+        pass
+
+    @abstractmethod
+    def severity(self) -> SeverityLevel:
+        """Return severity level of the rule."""
+        pass
+
+    @abstractmethod
+    def category(self) -> FindingCategory:
+        """Return category of the rule."""
+        pass
+
+    def supports_language(self, language: str) -> bool:
+        """Check if analyzer supports a language."""
+        return True