diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
new file mode 100644
index 0000000..31f4212
--- /dev/null
+++ b/.pre-commit-config.yaml
@@ -0,0 +1,48 @@
+# =============================================================================
+# MedeX — Pre-commit Hooks Configuration
+# =============================================================================
+# Install: pip install pre-commit && pre-commit install
+# Run all: pre-commit run --all-files
+# Update:  pre-commit autoupdate
+# =============================================================================
+
+repos:
+  # ── Black (code formatter) ─────────────────────────────────────────────
+  - repo: https://github.com/psf/black
+    rev: 24.10.0
+    hooks:
+      - id: black
+        language_version: python3
+        args: [--config=pyproject.toml]
+
+  # ── Ruff (linter + import sorter) ──────────────────────────────────────
+  - repo: https://github.com/astral-sh/ruff-pre-commit
+    rev: v0.8.6
+    hooks:
+      - id: ruff
+        args: [--fix, --exit-non-zero-on-fix]
+
+  # ── General file hygiene ───────────────────────────────────────────────
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v5.0.0
+    hooks:
+      - id: trailing-whitespace
+        args: [--markdown-linebreak-ext=md]
+      - id: end-of-file-fixer
+      - id: check-yaml
+      - id: check-toml
+      - id: check-json
+        exclude: ".vscode/"
+      - id: check-added-large-files
+        args: [--maxkb=500]
+      - id: check-merge-conflict
+      - id: debug-statements
+      - id: detect-private-key
+
+  # ── Security (bandit) ──────────────────────────────────────────────────
+  - repo: https://github.com/PyCQA/bandit
+    rev: 1.8.3
+    hooks:
+      - id: bandit
+        args: [-r, src/, -c, pyproject.toml, -ll]
+        pass_filenames: false
diff --git a/pyproject.toml b/pyproject.toml
index f66ba89..a6e2ee0 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -94,6 +94,8 @@ exclude = '''
 [tool.ruff]
 line-length = 88
 target-version = "py310"
+
+[tool.ruff.lint]
 select = [
     "E",    # pycodestyle errors
     "W",    # pycodestyle warnings
@@ -108,7 +110,7 @@ ignore = [
     "B008",  # do not perform function calls in argument defaults
 ]
 
-[tool.ruff.isort]
+[tool.ruff.lint.isort]
 known-first-party = ["medex"]
 
 [tool.mypy]
diff --git a/src/medex/agent/controller.py b/src/medex/agent/controller.py
index 51de0cd..a1aa214 100644
--- a/src/medex/agent/controller.py
+++ b/src/medex/agent/controller.py
@@ -619,7 +619,7 @@ def set_rag_service(self, service: Any) -> None:
 
     def set_memory_service(self, service: Any) -> None:
         """Set memory service."""
-        self.memory_service = memory_service
+        self.memory_service = service
 
     # =========================================================================
     # Main Entry Points
@@ -657,7 +657,7 @@ async def process(
                 logger.warning(f"Failed to load history: {e}")
 
         # Initialize state
-        state = self.state_manager.initialize(context)
+        self.state_manager.initialize(context)
 
         try:
             # Run agent loop
@@ -713,7 +713,7 @@ async def process_stream(
         )
 
         # Initialize state
-        state = self.state_manager.initialize(context)
+        self.state_manager.initialize(context)
 
         # Setup event forwarding
         event_queue: asyncio.Queue[AgentEvent] = asyncio.Queue()
@@ -837,7 +837,7 @@ async def _handle_emergency(self, context: AgentContext) -> AgentResult:
         # Add any tool results
         if context.tool_results:
             emergency_response += "**Assessment:**\n"
-            for tool, result in context.tool_results.items():
+            for _tool, result in context.tool_results.items():
                 if isinstance(result, dict):
                     emergency_response += f"- {result.get('recommendation', '')}\n"
 
diff --git a/src/medex/api/__init__.py b/src/medex/api/__init__.py
index 27f24d1..d5ae3ed 100644
--- a/src/medex/api/__init__.py
+++ b/src/medex/api/__init__.py
@@ -82,13 +82,11 @@
     ConnectionState,
     WebSocketHandler,
     WSCloseCode,
-)
-from .websocket import WSMessage as WebSocketMessage
-from .websocket import (
     WSMessageType,
     create_connection_manager,
     create_websocket_handler,
 )
+from .websocket import WSMessage as WebSocketMessage
 
 __all__ = [
     # App
diff --git a/src/medex/api/middleware.py b/src/medex/api/middleware.py
index 32485e8..5a8e655 100644
--- a/src/medex/api/middleware.py
+++ b/src/medex/api/middleware.py
@@ -21,7 +21,7 @@
 from typing import TYPE_CHECKING, Any
 
 if TYPE_CHECKING:
-    pass
+    from .models import ErrorCode
 
 
 # =============================================================================
diff --git a/src/medex/api/routes/tools.py b/src/medex/api/routes/tools.py
index 8a157b7..8e93cd6 100644
--- a/src/medex/api/routes/tools.py
+++ b/src/medex/api/routes/tools.py
@@ -14,6 +14,7 @@
 
 from __future__ import annotations
 
+import logging
 from datetime import datetime
 from typing import Any
 
@@ -133,7 +134,7 @@ async def check_interactions(
     """
     try:
         # Call the tool directly (synchronous, uses local dictionary)
-        result: DrugInteractionResult = await check_drug_interactions(
+        result: DrugInteractionResult = await check_drug_interactions(  # noqa: F821
             drugs=request.drugs
         )
 
@@ -161,7 +162,7 @@ async def check_interactions(
         logger.error(f"Drug interaction check failed: {e}")
         raise HTTPException(
             status_code=500, detail=f"Error checking interactions: {str(e)}"
-        )
+        ) from e
 
 
 # =============================================================================
@@ -184,7 +185,7 @@ async def calculate_drug_dosage(request: DosageRequest) -> DosageResponse:
     """
     try:
         # Call the tool directly
-        result: DosageResult = await calculate_dosage(
+        result: DosageResult = await calculate_dosage(  # noqa: F821
             drug_name=request.drug_name,
             patient_weight_kg=request.patient_weight,
             patient_age_years=request.patient_age,
@@ -207,7 +208,7 @@ async def calculate_drug_dosage(request: DosageRequest) -> DosageResponse:
         logger.error(f"Dosage calculation failed: {e}")
         raise HTTPException(
             status_code=500, detail=f"Error calculating dosage: {str(e)}"
-        )
+        ) from e
 
 
 # =============================================================================
@@ -230,7 +231,7 @@ async def interpret_lab(request: LabInterpretRequest) -> LabInterpretResponse:
     """
     try:
         # Call the tool directly
-        result: LabInterpretationResult = await interpret_lab_value(
+        result: LabInterpretationResult = await interpret_lab_value(  # noqa: F821
             test_name=request.test_name,
             value=request.value,
             unit=request.unit,
@@ -254,7 +255,7 @@ async def interpret_lab(request: LabInterpretRequest) -> LabInterpretResponse:
         logger.error(f"Lab interpretation failed: {e}")
         raise HTTPException(
             status_code=500, detail=f"Error interpreting lab value: {str(e)}"
-        )
+        ) from e
 
 
 # =============================================================================
diff --git a/src/medex/db/repositories.py b/src/medex/db/repositories.py
index ae1fa54..9c74473 100644
--- a/src/medex/db/repositories.py
+++ b/src/medex/db/repositories.py
@@ -981,8 +981,9 @@ async def get_metrics_by_tool(
                 func.avg(ToolExecution.latency_ms).label("avg_latency"),
                 func.sum(
                     func.cast(
-                        ToolExecution.cache_hit == True, type_=func.Integer
-                    )  # noqa: E712
+                        ToolExecution.cache_hit == True,  # noqa: E712
+                        type_=func.Integer,
+                    )
                 ).label("cache_hits"),
             )
             .where(ToolExecution.tool_name == tool_name)
diff --git a/src/medex/llm/parser.py b/src/medex/llm/parser.py
index 83aae87..c4b6be5 100644
--- a/src/medex/llm/parser.py
+++ b/src/medex/llm/parser.py
@@ -547,7 +547,7 @@ def _extract_entities(self, content: str) -> dict[str, list[str]]:
         # Extract CIE-10 codes
         if self.config.extract_cie10:
             cie10_matches = CIE10_PATTERN.findall(content)
-            entities["cie10_codes"] = list(set(c.upper() for c in cie10_matches))
+            entities["cie10_codes"] = list({c.upper() for c in cie10_matches})
 
         # Extract drug mentions
         if self.config.extract_drugs:
diff --git a/src/medex/llm/router.py b/src/medex/llm/router.py
index 854fed3..94fa736 100644
--- a/src/medex/llm/router.py
+++ b/src/medex/llm/router.py
@@ -472,7 +472,7 @@ async def stream(self, request: LLMRequest) -> AsyncIterator[StreamChunk]:
 
             # Emit finish event
             latency_ms = (time.time() - start_time) * 1000
-            ttft_ms = (
+            _ttft_ms = (
                 (first_token_time - start_time) * 1000 if first_token_time else None
             )
 
diff --git a/src/medex/llm/service.py b/src/medex/llm/service.py
index 0340227..ad3dfbc 100644
--- a/src/medex/llm/service.py
+++ b/src/medex/llm/service.py
@@ -278,7 +278,7 @@ async def query(
         )
 
         # Execute request
-        start_time = time.time()
+        _start_time = time.time()
 
         if use_stream:
             # Collect streaming response
diff --git a/src/medex/medical/formatter.py b/src/medex/medical/formatter.py
index 0e50913..85a5c02 100644
--- a/src/medex/medical/formatter.py
+++ b/src/medex/medical/formatter.py
@@ -26,6 +26,7 @@
     DiagnosticHypothesis,
     DiagnosticPlan,
     Medication,
+    Specialty,
     TreatmentPlan,
     TriageAssessment,
     TriageLevel,
diff --git a/src/medex/medical/models.py b/src/medex/medical/models.py
index 456ab14..91c78d5 100644
--- a/src/medex/medical/models.py
+++ b/src/medex/medical/models.py
@@ -556,7 +556,7 @@ def to_dict(self) -> dict[str, Any]:
             "symptoms": [s.to_dict() for s in self.symptoms],
             "vital_signs": self.vital_signs.to_dict() if self.vital_signs else None,
             "physical_exam": self.physical_exam,
-            "lab_values": [l.to_dict() for l in self.lab_values],
+            "lab_values": [lv.to_dict() for lv in self.lab_values],
             "imaging": self.imaging,
             "triage": self.triage.to_dict() if self.triage else None,
             "differential_diagnosis": [
diff --git a/src/medex/medical/reasoner.py b/src/medex/medical/reasoner.py
index 5dbfc20..61a5bc7 100644
--- a/src/medex/medical/reasoner.py
+++ b/src/medex/medical/reasoner.py
@@ -340,7 +340,7 @@ def analyze(self, case: ClinicalCase) -> list[DiagnosticHypothesis]:
 
         # Build hypotheses
         hypotheses = []
-        for dx_id, score, dx_pattern in scored_diagnoses[
+        for _dx_id, score, dx_pattern in scored_diagnoses[
             : self.config.max_differential
         ]:
             hypothesis = self._build_hypothesis(
@@ -425,7 +425,7 @@ def _calculate_diagnosis_score(
         pattern_labs = dx_pattern.get("labs", [])
         if pattern_labs:
             lab_text = " ".join(lab_findings)
-            matches = sum(1 for l in pattern_labs if l in lab_text)
+            matches = sum(1 for lab in pattern_labs if lab in lab_text)
             lab_score = matches / len(pattern_labs)
         elif lab_findings:
             lab_score = 0.1  # Some credit for having labs
@@ -464,9 +464,9 @@ def _build_hypothesis(
             if s in symptoms_text:
                 supporting.append(f"Presenta: {s}")
 
-        for l in dx_pattern.get("labs", []):
-            if any(l in lf for lf in lab_findings):
-                supporting.append(f"Laboratorio: {l}")
+        for lab in dx_pattern.get("labs", []):
+            if any(lab in lf for lf in lab_findings):
+                supporting.append(f"Laboratorio: {lab}")
 
         # Determine next steps
         next_steps = self._get_diagnostic_steps(dx_pattern, case)
@@ -539,7 +539,7 @@ def _get_diagnostic_steps(
             )
 
         # Always add basic labs if not already ordered
-        existing_labs = {l.name.lower() for l in case.lab_values}
+        existing_labs = {lv.name.lower() for lv in case.lab_values}
         if "hemograma" not in existing_labs and "hemoglobina" not in existing_labs:
             steps.append("Hemograma completo")
         if "bioquímica" not in existing_labs:
diff --git a/src/medex/rag/chunker.py b/src/medex/rag/chunker.py
index 27d5e5b..3484511 100644
--- a/src/medex/rag/chunker.py
+++ b/src/medex/rag/chunker.py
@@ -147,7 +147,7 @@ def chunk(self, document: Document) -> list[Chunk]:
         sections = self._split_into_sections(content)
 
         char_offset = 0
-        for section_idx, (header, section_content) in enumerate(sections):
+        for _section_idx, (header, section_content) in enumerate(sections):
             section_chunks = self._chunk_section(
                 section_content,
                 document_id=document.id,
diff --git a/src/medex/rag/embedder.py b/src/medex/rag/embedder.py
index e117929..74895d1 100644
--- a/src/medex/rag/embedder.py
+++ b/src/medex/rag/embedder.py
@@ -139,7 +139,7 @@ async def embed_chunks(self, chunks: list[Chunk]) -> list[Chunk]:
         texts = [c.content for c in chunks]
         embeddings = await self.embed_texts(texts)
 
-        for chunk, embedding in zip(chunks, embeddings):
+        for chunk, embedding in zip(chunks, embeddings, strict=False):
             chunk.embedding = embedding.vector
 
         return chunks
@@ -300,7 +300,7 @@ async def embed_texts(self, texts: list[str]) -> list[Embedding]:
                 all_vectors.extend(batch_vectors)
 
             # Fill in results and cache
-            for idx, vector in zip(uncached_indices, all_vectors):
+            for idx, vector in zip(uncached_indices, all_vectors, strict=False):
                 embeddings[idx] = Embedding(
                     vector=vector,
                     model=self.config.model_name,
@@ -428,7 +428,7 @@ async def embed_texts(self, texts: list[str]) -> list[Embedding]:
                 all_vectors.extend(batch_vectors)
 
             # Fill results
-            for idx, vector in zip(uncached_indices, all_vectors):
+            for idx, vector in zip(uncached_indices, all_vectors, strict=False):
                 if self.config.normalize:
                     vector = self._normalize(vector)
 
diff --git a/src/medex/rag/reranker.py b/src/medex/rag/reranker.py
index c6de71a..fd738ac 100644
--- a/src/medex/rag/reranker.py
+++ b/src/medex/rag/reranker.py
@@ -156,7 +156,7 @@ async def rerank(
         normalized_scores = [(s - min_score) / score_range for s in scores]
 
         # Update results with rerank scores
-        for result, rerank_score in zip(results, normalized_scores):
+        for result, rerank_score in zip(results, normalized_scores, strict=False):
             result.rerank_score = float(rerank_score)
             result.relevance = self._score_to_relevance(rerank_score)
 
@@ -540,7 +540,8 @@ async def rerank(
             chunk_scores = all_scores[result.chunk.id]
             if chunk_scores:
                 weighted_score = (
-                    sum(s * w for s, w in zip(chunk_scores, weights)) / total_weight
+                    sum(s * w for s, w in zip(chunk_scores, weights, strict=False))
+                    / total_weight
                 )
                 result.rerank_score = weighted_score
                 result.relevance = self._score_to_relevance(weighted_score)
diff --git a/src/medex/security/audit.py b/src/medex/security/audit.py
index 1d9f4bd..c03a300 100644
--- a/src/medex/security/audit.py
+++ b/src/medex/security/audit.py
@@ -56,7 +56,7 @@ async def count(self, query: AuditQuery) -> int:
         """Count matching events."""
         pass
 
-    async def close(self) -> None:
+    async def close(self) -> None:  # noqa: B027
         """Close backend connection."""
         pass
 
diff --git a/src/medex/tools/medical/emergency_detector.py b/src/medex/tools/medical/emergency_detector.py
index 906b0cb..de9652d 100644
--- a/src/medex/tools/medical/emergency_detector.py
+++ b/src/medex/tools/medical/emergency_detector.py
@@ -347,7 +347,7 @@ async def detect_emergency(
     symptoms_text = " ".join(symptoms_lower)
 
     # Check each red flag pattern
-    for flag_id, flag_data in RED_FLAGS.items():
+    for _flag_id, flag_data in RED_FLAGS.items():
         matched = False
 
         # Check primary symptoms
@@ -596,7 +596,7 @@ async def check_critical_values(
         normalized_values[normalized_key] = value
 
     # Check each critical value
-    for crit_id, crit_data in CRITICAL_VALUES.items():
+    for _crit_id, crit_data in CRITICAL_VALUES.items():
         param = crit_data["parameter"].lower().replace(" ", "_")
 
         # Check if this parameter is in the provided values
diff --git a/tests/e2e/test_ui_e2e.py b/tests/e2e/test_ui_e2e.py
index a546da0..abd8efc 100644
--- a/tests/e2e/test_ui_e2e.py
+++ b/tests/e2e/test_ui_e2e.py
@@ -200,9 +200,9 @@ def test_page_has_lang_attribute(self, page: Page, medex_url: str):
         """HTML has lang attribute"""
         page.goto(medex_url, wait_until="networkidle")
 
-        html_lang = page.locator("html").get_attribute("lang")
-        # Streamlit may not set this, so we just check it exists
-        # assert html_lang is not None
+        _html_lang = page.locator("html").get_attribute("lang")
+        # Reflex should set lang attribute
+        # assert _html_lang is not None
 
     @pytest.mark.e2e
     def test_images_have_alt_text(self, page: Page, medex_url: str):
diff --git a/tests/test_differential_diagnosis.py b/tests/test_differential_diagnosis.py
index 5a15fa6..1b2ab2d 100644
--- a/tests/test_differential_diagnosis.py
+++ b/tests/test_differential_diagnosis.py
@@ -206,7 +206,7 @@ def test_fuzzy_match_synonyms(self):
             ("vomitos", "náuseas"),  # Similar
         ]
 
-        for query, expected_symptom in test_cases:
+        for query, _expected_symptom in test_cases:
             result = get_differential_for_symptom(query)
             # Puede que no todos hagan match fuzzy, pero verificamos que no crashee
             # y que los que sí existen funcionen
diff --git a/tests/test_infrastructure.py b/tests/test_infrastructure.py
index 1f8ece4..3e3c076 100644
--- a/tests/test_infrastructure.py
+++ b/tests/test_infrastructure.py
@@ -508,14 +508,14 @@ async def test_full_conversation_flow(self, db_session, redis_client):
 
         messages_for_cache = []
 
-        for i, (role, content) in enumerate(
+        for _i, (role, content) in enumerate(
             [
                 (MessageRole.USER, "What is hypertension?"),
                 (MessageRole.ASSISTANT, "Hypertension is high blood pressure..."),
                 (MessageRole.USER, "What are the symptoms?"),
             ]
         ):
-            msg = await msg_repo.create_message(
+            msg = await msg_repo.create_message(  # noqa: F841
                 conversation_id=conv.id,
                 role=role,
                 content=content,
diff --git a/tests/test_medex_logger.py b/tests/test_medex_logger.py
index 7ea0ab1..8d5bd1d 100644
--- a/tests/test_medex_logger.py
+++ b/tests/test_medex_logger.py
@@ -67,7 +67,7 @@ class TestLoggerInitialization:
     def test_logger_creates_log_directory(self, temp_log_dir):
         """Verifica que se crea el directorio de logs."""
         log_path = Path(temp_log_dir) / "new_logs"
-        logger = MedeXLogger(log_dir=str(log_path), enable_console=False)
+        _logger = MedeXLogger(log_dir=str(log_path), enable_console=False)
         assert log_path.exists()
 
     def test_logger_generates_session_id(self, logger):
@@ -426,7 +426,7 @@ def test_audit_trail_entry(self):
 
         d = audit.to_dict()
         assert d["action"] == "test_action"
-        assert d["success"] == True
+        assert d["success"] is True
 
 
 # ============================================================================
diff --git a/tests/test_observability.py b/tests/test_observability.py
index 55f6cc6..538ac42 100644
--- a/tests/test_observability.py
+++ b/tests/test_observability.py
@@ -267,8 +267,8 @@ def test_create_span(self, tracer: Tracer) -> None:
 
     def test_nested_spans(self, tracer: Tracer) -> None:
         """Test nested spans share trace ID."""
-        with tracer.start_span("parent") as parent:
-            with tracer.start_span("child") as child:
+        with tracer.start_span("parent") as parent:  # noqa: F841
+            with tracer.start_span("child") as child:  # noqa: F841
                 pass
 
         tracer.flush()
@@ -300,7 +300,7 @@ def test_span_attributes(self, tracer: Tracer) -> None:
     def test_span_error(self, tracer: Tracer) -> None:
         """Test span error handling."""
         try:
-            with tracer.start_span("error_span") as span:
+            with tracer.start_span("error_span") as span:  # noqa: F841
                 raise ValueError("Test error")
         except ValueError:
             pass
@@ -316,7 +316,7 @@ def test_span_duration(self, tracer: Tracer) -> None:
         """Test span duration calculation."""
         import time
 
-        with tracer.start_span("timed_span") as span:
+        with tracer.start_span("timed_span") as span:  # noqa: F841
             time.sleep(0.01)
 
         tracer.flush()