diff --git a/hippocortex/__init__.py b/hippocortex/__init__.py
index ffd8282..f56a346 100644
--- a/hippocortex/__init__.py
+++ b/hippocortex/__init__.py
@@ -1,33 +1,63 @@
 from __future__ import annotations
 
 import logging
-from dataclasses import dataclass
+from dataclasses import dataclass, field
+from time import perf_counter
 
 from hippocortex.config import HippoConfig
 from hippocortex.embedders.base import Embedder
 from hippocortex.embedders.dummy_embedder import DummyEmbedder
 from hippocortex.hippo.episodic_store import SQLiteEpisodicStore
+from hippocortex.observability import configure_json_logger
 from hippocortex.registry import get_consolidation_strategy, get_router_strategy, get_storage_backend, register_defaults
+from hippocortex.telemetry import NoOpTelemetry, Telemetry
 from hippocortex.types import ConsolidationOutput, ContextPack
 from hippocortex.working_memory import WorkingMemory
 
 
 logger = logging.getLogger(__name__)
+configure_json_logger(logger)
 
 
 class CortexAPI:
     def __init__(self, sdk: "HippoCortex") -> None:
         self._sdk = sdk
 
-    def search(self, agent_id: str, query: str, k: int = 5, filters: dict | None = None):
+    def search(
+        self,
+        agent_id: str,
+        query: str,
+        k: int = 5,
+        filters: dict | None = None,
+        session_id: str | None = None,
+        request_id: str | None = None,
+    ):
+        started = perf_counter()
         vector = self._sdk.embedder.embed_text(query)
-        return self._sdk.semantic_store.search(agent_id=agent_id, query_vector=vector, k=k, filters=filters)
+        hits = self._sdk.semantic_store.search(agent_id=agent_id, query_vector=vector, k=k, filters=filters)
+        duration_ms = (perf_counter() - started) * 1000
+        hit_rate = len(hits) / k if k > 0 else 0.0
+        tags = {"agent_id": agent_id}
+        self._sdk.telemetry.observe("hippocortex.search.duration_ms", duration_ms, tags=tags)
+        self._sdk.telemetry.observe("hippocortex.search.hit_rate", hit_rate, tags=tags)
+        logger.info(
+            "search_completed",
+            extra={
+                "agent_id": agent_id,
+                "session_id": session_id,
+                "request_id": request_id,
+                "duration_ms": duration_ms,
+                "hit_rate": hit_rate,
+            },
+        )
+        return hits
 
 
 @dataclass
 class HippoCortex:
     config: HippoConfig
     embedder: Embedder
+    telemetry: Telemetry = field(default_factory=NoOpTelemetry)
 
     def __post_init__(self) -> None:
         register_defaults()
@@ -40,7 +70,7 @@ def __post_init__(self) -> None:
                 f"model.embedding_dim {self.config.model.embedding_dim}"
             )
 
-        self.hippo = SQLiteEpisodicStore(self.config.storage.db_path)
+        self.hippo = SQLiteEpisodicStore(self.config.storage.db_path, telemetry=self.telemetry)
         semantic_backend = self.config.storage.semantic_store_backend.lower()
         self.semantic_store = get_storage_backend(semantic_backend, self.config, self.embedder.dimension)
         self.cortex = CortexAPI(self)
@@ -56,22 +86,64 @@ def default(cls, config: HippoConfig | None = None, embedder: Embedder | None =
         emb = embedder or DummyEmbedder(dimension=cfg.model.embedding_dim)
         return cls(config=cfg, embedder=emb)
 
-    def consolidate(self, agent_id: str, session_id: str | None = None, strategy: str = "replay_v1") -> ConsolidationOutput:
+    def consolidate(
+        self,
+        agent_id: str,
+        session_id: str | None = None,
+        strategy: str = "replay_v1",
+        request_id: str | None = None,
+    ) -> ConsolidationOutput:
+        started = perf_counter()
         consolidator = self._consolidators.get(strategy)
         if consolidator is None:
             consolidator = get_consolidation_strategy(strategy, self.config)
             self._consolidators[strategy] = consolidator
         episodes = consolidator.select_episodes(self.hippo, agent_id=agent_id, session_id=session_id)
-        return consolidator.run(agent_id=agent_id, episodes=episodes, embedder=self.embedder, semantic_store=self.semantic_store)
-
-    def build_context(self, agent_id: str, session_id: str, user_message: str, max_tokens: int) -> ContextPack:
+        output = consolidator.run(agent_id=agent_id, episodes=episodes, embedder=self.embedder, semantic_store=self.semantic_store)
+        duration_ms = (perf_counter() - started) * 1000
+        self.telemetry.observe("hippocortex.consolidation.duration_ms", duration_ms, tags={"agent_id": agent_id, "strategy": strategy})
+        logger.info(
+            "consolidation_completed",
+            extra={
+                "agent_id": agent_id,
+                "session_id": session_id,
+                "request_id": request_id,
+                "duration_ms": duration_ms,
+            },
+        )
+        return output
+
+    def build_context(
+        self,
+        agent_id: str,
+        session_id: str,
+        user_message: str,
+        max_tokens: int,
+        request_id: str | None = None,
+    ) -> ContextPack:
         decision = self.router.route(user_message=user_message, max_tokens=max_tokens)
+        logger.info(
+            "router_decision",
+            extra={
+                "agent_id": agent_id,
+                "session_id": session_id,
+                "request_id": request_id,
+                "intent": decision.intent,
+                "explain": decision.explain,
+            },
+        )
         recent_events = self.hippo.list_events(agent_id=agent_id, session_id=session_id, limit=self.config.runtime.working_memory_turns)
         selected_recent = self.working_memory.select_recent(recent_events, token_budget=decision.working_memory_tokens)
 
         semantic_notes = []
         if decision.intent in {"semantic", "hybrid"}:
-            semantic_notes = self.cortex.search(agent_id=agent_id, query=user_message, k=5)
+            semantic_notes = self.cortex.search(
+                agent_id=agent_id,
+                session_id=session_id,
+                query=user_message,
+                k=5,
+                request_id=request_id,
+            )
 
         highlights = []
         if decision.include_highlights:
diff --git a/hippocortex/hippo/episodic_store.py b/hippocortex/hippo/episodic_store.py
index 75e5174..a198b5a 100644
--- a/hippocortex/hippo/episodic_store.py
+++ b/hippocortex/hippo/episodic_store.py
@@ -1,16 +1,22 @@
 from __future__ import annotations
 
 import json
+import logging
 import sqlite3
 from datetime import datetime
 from pathlib import Path
 
+from hippocortex.observability import configure_json_logger
+from hippocortex.telemetry import NoOpTelemetry, Telemetry
 from hippocortex.types import EventRecord
 
 
 class SQLiteEpisodicStore:
-    def __init__(self, db_path: str) -> None:
+    def __init__(self, db_path: str, telemetry: Telemetry | None = None) -> None:
         self.db_path = db_path
+        self.telemetry = telemetry or NoOpTelemetry()
+        self.logger = logging.getLogger("hippocortex.observability")
+        configure_json_logger(self.logger)
         Path(db_path).parent.mkdir(parents=True, exist_ok=True) if Path(db_path).parent != Path(".") else None
         self._init_db()
 
@@ -48,6 +54,7 @@ def add_event(
         content: str,
         metadata: dict | None = None,
         importance: float = 0.5,
+        request_id: str | None = None,
     ) -> EventRecord:
         event = EventRecord(
             agent_id=agent_id,
@@ -76,6 +83,17 @@ def add_event(
             )
             conn.commit()
             event.id = int(cur.lastrowid)
+        self.telemetry.increment("hippocortex.events.write", value=1, tags={"agent_id": agent_id, "session_id": session_id})
+        self.logger.info(
+            "event_written",
+            extra={
+                "agent_id": agent_id,
+                "session_id": session_id,
+                "request_id": request_id,
+                "metric": "hippocortex.events.write",
+                "value": 1,
+            },
+        )
         return event
 
     def list_events(self, agent_id: str, session_id: str | None = None, limit: int = 50) -> list[EventRecord]:
diff --git a/hippocortex/observability.py b/hippocortex/observability.py
new file mode 100644
index 0000000..e1bcccc
--- /dev/null
+++ b/hippocortex/observability.py
@@ -0,0 +1,33 @@
+from __future__ import annotations
+
+import json
+import logging
+from datetime import datetime, timezone
+
+
+class JsonFormatter(logging.Formatter):
+    def format(self, record: logging.LogRecord) -> str:
+        payload = {
+            "timestamp": datetime.now(timezone.utc).isoformat(),
+            "level": record.levelname,
+            "logger": record.name,
+            "message": record.getMessage(),
+            "agent_id": getattr(record, "agent_id", None),
+            "session_id": getattr(record, "session_id", None),
+            "request_id": getattr(record, "request_id", None),
+        }
+        for key in ("intent", "metric", "value", "duration_ms", "hit_rate", "explain"):
+            if hasattr(record, key):
+                payload[key] = getattr(record, key)
+        return json.dumps(payload, ensure_ascii=False)
+
+
+def configure_json_logger(logger: logging.Logger) -> None:
+    if logger.handlers:
+        return
+    handler = logging.StreamHandler()
+    handler.setFormatter(JsonFormatter())
+    logger.addHandler(handler)
+    logger.setLevel(logging.INFO)
+    logger.propagate = False
+
diff --git a/hippocortex/router.py b/hippocortex/router.py
index 4d2cd29..37af8a8 100644
--- a/hippocortex/router.py
+++ b/hippocortex/router.py
@@ -9,8 +9,10 @@ def route(self, user_message: str, max_tokens: int) -> RoutingDecision:
         semantic_keywords = ["remember", "history", "why", "pattern", "summarize", "context"]
         episodic_keywords = ["just now", "latest", "last message", "session"]
 
-        semantic_score = sum(1 for k in semantic_keywords if k in lowered)
-        episodic_score = sum(1 for k in episodic_keywords if k in lowered)
+        matched_semantic = [k for k in semantic_keywords if k in lowered]
+        matched_episodic = [k for k in episodic_keywords if k in lowered]
+        semantic_score = len(matched_semantic)
+        episodic_score = len(matched_episodic)
 
         if semantic_score > episodic_score:
             intent = "semantic"
@@ -26,4 +28,15 @@ def route(self, user_message: str, max_tokens: int) -> RoutingDecision:
             working_memory_tokens=wm_tokens,
             semantic_tokens=semantic_tokens,
             include_highlights=intent != "semantic",
+            explain={
+                "matched_keywords": {
+                    "semantic": matched_semantic,
+                    "episodic": matched_episodic,
+                },
+                "scores": {"semantic": semantic_score, "episodic": episodic_score},
+                "budget_allocation": {
+                    "working_memory_tokens": wm_tokens,
+                    "semantic_tokens": semantic_tokens,
+                },
+            },
         )
diff --git a/hippocortex/telemetry.py b/hippocortex/telemetry.py
new file mode 100644
index 0000000..ffd1ea0
--- /dev/null
+++ b/hippocortex/telemetry.py
@@ -0,0 +1,36 @@
+from __future__ import annotations
+
+from dataclasses import dataclass, field
+from typing import Protocol
+
+
+class Telemetry(Protocol):
+    def increment(self, metric: str, value: int = 1, tags: dict[str, str] | None = None) -> None: ...
+
+    def observe(self, metric: str, value: float, tags: dict[str, str] | None = None) -> None: ...
+
+
+@dataclass
+class NoOpTelemetry:
+    """Default telemetry backend that safely drops all metrics."""
+
+    def increment(self, metric: str, value: int = 1, tags: dict[str, str] | None = None) -> None:
+        return None
+
+    def observe(self, metric: str, value: float, tags: dict[str, str] | None = None) -> None:
+        return None
+
+
+@dataclass
+class InMemoryTelemetry:
+    """Testing helper backend that records every metric call."""
+
+    counters: list[tuple[str, int, dict[str, str]]] = field(default_factory=list)
+    observations: list[tuple[str, float, dict[str, str]]] = field(default_factory=list)
+
+    def increment(self, metric: str, value: int = 1, tags: dict[str, str] | None = None) -> None:
+        self.counters.append((metric, value, tags or {}))
+
+    def observe(self, metric: str, value: float, tags: dict[str, str] | None = None) -> None:
+        self.observations.append((metric, value, tags or {}))
+
diff --git a/hippocortex/types.py b/hippocortex/types.py
index cec01da..1a7db85 100644
--- a/hippocortex/types.py
+++ b/hippocortex/types.py
@@ -65,6 +65,7 @@ class RoutingDecision(BaseModel):
     working_memory_tokens: int
     semantic_tokens: int
     include_highlights: bool = True
+    explain: dict[str, Any] = Field(default_factory=dict)
 
 
 class ConsolidationOutput(BaseModel):
diff --git a/tests/test_observability.py b/tests/test_observability.py
new file mode 100644
index 0000000..edaff0a
--- /dev/null
+++ b/tests/test_observability.py
@@ -0,0 +1,77 @@
+import logging
+
+from hippocortex import DummyEmbedder, HippoConfig, HippoCortex
+from hippocortex.config import ModelConfig, StorageConfig
+from hippocortex.telemetry import InMemoryTelemetry
+
+
+def _build_sdk(tmp_path):
+    db_path = tmp_path / "memory.db"
+    telemetry = InMemoryTelemetry()
+    sdk = HippoCortex.default(
+        config=HippoConfig(
+            storage=StorageConfig(db_path=str(db_path)),
+            model=ModelConfig(embedding_dim=8),
+        ),
+        embedder=DummyEmbedder(dimension=8),
+    )
+    sdk.telemetry = telemetry
+    sdk.hippo.telemetry = telemetry
+    return sdk, telemetry
+
+
+def test_router_explain_contains_keywords_and_budget():
+    decision = HippoCortex.default().router.route("summarize latest history", max_tokens=100)
+    assert "matched_keywords" in decision.explain
+    assert "budget_allocation" in decision.explain
+
+
+def test_observability_logs_include_required_fields(tmp_path):
+    sdk, _ = _build_sdk(tmp_path)
+    records = []
+
+    class CaptureHandler(logging.Handler):
+        def emit(self, record):
+            records.append(record)
+
+    handler = CaptureHandler()
+    logger = logging.getLogger("hippocortex")
+    obs_logger = logging.getLogger("hippocortex.observability")
+    logger.addHandler(handler)
+    obs_logger.addHandler(handler)
+
+    try:
+        sdk.hippo.add_event("agent-1", "session-1", "user", "I like tea", request_id="req-1")
+        sdk.consolidate(agent_id="agent-1", session_id="session-1", request_id="req-1")
+        sdk.build_context(
+            agent_id="agent-1",
+            session_id="session-1",
+            user_message="summarize history",
+            max_tokens=100,
+            request_id="req-1",
+        )
+    finally:
+        logger.removeHandler(handler)
+        obs_logger.removeHandler(handler)
+
+    assert records
+    for record in records:
+        assert hasattr(record, "agent_id")
+        assert hasattr(record, "session_id")
+        assert hasattr(record, "request_id")
+
+
+def test_telemetry_metrics_emitted(tmp_path):
+    sdk, telemetry = _build_sdk(tmp_path)
+
+    sdk.hippo.add_event("agent-1", "session-1", "user", "I like tea", request_id="req-1")
+    sdk.consolidate(agent_id="agent-1", session_id="session-1", request_id="req-1")
+    sdk.cortex.search(agent_id="agent-1", session_id="session-1", query="tea", k=5, request_id="req-1")
+
+    counter_names = [name for name, _, _ in telemetry.counters]
+    assert "hippocortex.events.write" in counter_names
+
+    observation_names = [name for name, _, _ in telemetry.observations]
+    assert "hippocortex.consolidation.duration_ms" in observation_names
+    assert "hippocortex.search.duration_ms" in observation_names
+    assert "hippocortex.search.hit_rate" in observation_names