diff --git a/core/src/agentforge_core/llm/base.py b/core/src/agentforge_core/llm/base.py
new file mode 100644
index 0000000..effed53
--- /dev/null
+++ b/core/src/agentforge_core/llm/base.py
@@ -0,0 +1,38 @@
+"""Tipos y Protocol del proveedor LLM (Strategy pattern)."""
+
+from __future__ import annotations
+
+from typing import Any, Literal, Protocol
+
+from pydantic import BaseModel
+
+
+class Message(BaseModel):
+    """Mensaje individual de la conversación enviada al LLM."""
+
+    role: Literal["system", "user", "assistant"]
+    content: str
+
+
+class CompletionResult(BaseModel):
+    """Resultado normalizado de una llamada a un proveedor LLM."""
+
+    content: str
+    model: str
+    tokens_in: int
+    tokens_out: int
+    latency_ms: int
+
+
+class LLMProvider(Protocol):
+    """Interfaz mínima común a todos los proveedores LLM."""
+
+    name: str
+
+    async def complete(
+        self,
+        messages: list[Message],
+        schema: dict[str, Any] | None = None,
+        temperature: float = 0.2,
+        max_tokens: int = 2000,
+    ) -> CompletionResult: ...
diff --git a/tests/unit/test_llm_base.py b/tests/unit/test_llm_base.py
new file mode 100644
index 0000000..deefc98
--- /dev/null
+++ b/tests/unit/test_llm_base.py
@@ -0,0 +1,19 @@
+"""Test de los modelos base del proveedor LLM."""
+
+from agentforge_core.llm.base import CompletionResult, Message
+
+
+def test_message_serializable() -> None:
+    m = Message(role="user", content="hola")
+    assert m.model_dump()["role"] == "user"
+
+
+def test_completion_result_campos_basicos() -> None:
+    r = CompletionResult(
+        content='{"a": 1}',
+        model="gpt-4o-mock",
+        tokens_in=10,
+        tokens_out=20,
+        latency_ms=42,
+    )
+    assert r.tokens_in == 10