diff --git a/src/models.py b/src/models.py
new file mode 100644
index 0000000..57e9546
--- /dev/null
+++ b/src/models.py
@@ -0,0 +1,123 @@
+"""Data models for the prompt manager."""
+
+from dataclasses import dataclass, field
+from datetime import datetime
+from typing import Any
+
+
+@dataclass
+class PromptVariable:
+    """Definition of a template variable."""
+    name: str
+    description: str = ""
+    required: bool = True
+    default: str = ""
+
+
+@dataclass
+class Prompt:
+    """Represents a prompt template."""
+    name: str
+    template: str
+    description: str = ""
+    tags: list[str] = field(default_factory=list)
+    variables: list[dict[str, Any]] = field(default_factory=list)
+    provider: str = ""
+    model: str = ""
+    created_at: str = ""
+    updated_at: str = ""
+
+    def __post_init__(self):
+        if not self.created_at:
+            self.created_at = datetime.now().isoformat()
+        if not self.updated_at:
+            self.updated_at = datetime.now().isoformat()
+
+    def to_dict(self) -> dict[str, Any]:
+        """Convert prompt to dictionary."""
+        return {
+            "name": self.name,
+            "template": self.template,
+            "description": self.description,
+            "tags": self.tags,
+            "variables": self.variables,
+            "provider": self.provider,
+            "model": self.model,
+            "created_at": self.created_at,
+            "updated_at": self.updated_at,
+        }
+
+    @classmethod
+    def from_dict(cls, data: dict[str, Any]) -> "Prompt":
+        """Create prompt from dictionary."""
+        return cls(
+            name=data.get("name", ""),
+            template=data.get("template", ""),
+            description=data.get("description", ""),
+            tags=data.get("tags", []),
+            variables=data.get("variables", []),
+            provider=data.get("provider", ""),
+            model=data.get("model", ""),
+            created_at=data.get("created_at", ""),
+            updated_at=data.get("updated_at", ""),
+        )
+
+    def get_required_variables(self) -> list[str]:
+        """Get list of required variable names."""
+        return [
+            v["name"] for v in self.variables
+            if v.get("required", True)
+        ]
+
+
+@dataclass
+class Tag:
+    """Represents a tag with associated prompts."""
+    name: str
+    prompts: list[str] = field(default_factory=list)
+
+    def to_dict(self) -> dict[str, Any]:
+        """Convert tag to dictionary."""
+        return {
+            "name": self.name,
+            "prompts": self.prompts,
+        }
+
+    @classmethod
+    def from_dict(cls, data: dict[str, Any]) -> "Tag":
+        """Create tag from dictionary."""
+        return cls(
+            name=data.get("name", ""),
+            prompts=data.get("prompts", []),
+        )
+
+
+@dataclass
+class Config:
+    """Configuration settings."""
+    prompt_dir: str = "~/.config/llm-prompt-manager/prompts"
+    ollama_url: str = "http://localhost:11434"
+    lmstudio_url: str = "http://localhost:1234"
+    default_model: str = "llama3.2"
+    default_provider: str = "ollama"
+
+    def to_dict(self) -> dict[str, Any]:
+        """Convert config to dictionary."""
+        return {
+            "prompt_dir": self.prompt_dir,
+            "ollama_url": self.ollama_url,
+            "lmstudio_url": self.lmstudio_url,
+            "default_model": self.default_model,
+            "default_provider": self.default_provider,
+        }
+
+    @classmethod
+    def from_dict(cls, data: dict[str, Any]) -> "Config":
+        """Create config from dictionary."""
+        return cls(
+            prompt_dir=data.get("prompt_dir", cls.prompt_dir),
+            ollama_url=data.get("ollama_url", cls.ollama_url),
+            lmstudio_url=data.get("lmstudio_url", cls.lmstudio_url),
+            default_model=data.get("default_model", cls.default_model),
+            default_provider=data.get("default_provider", cls.default_provider),
+        )