diff --git a/lib/crewai/src/crewai/agent/core.py b/lib/crewai/src/crewai/agent/core.py
index 4f4c2368c..4c20693a8 100644
--- a/lib/crewai/src/crewai/agent/core.py
+++ b/lib/crewai/src/crewai/agent/core.py
@@ -401,10 +401,29 @@ class Agent(BaseAgent):
         return self.planning_config is not None or self.planning
 
     def _setup_agent_executor(self) -> None:
-        """Initialize the agent executor with a default cache handler."""
-        if not self.cache_handler:
-            self.cache_handler = CacheHandler()
-        self.set_cache_handler(self.cache_handler)
+        """Initialize the agent's tools handler and optional tool cache.
+
+        Tool-result caching is opt-in: a standalone agent gets a cache only
+        when it was constructed with an explicit ``cache=True`` or a
+        ``cache_handler``. Agents inside a crew additionally receive the
+        crew's shared handler when ``Crew(cache=True)``. Without an opt-in,
+        repeated tool calls with identical arguments always re-execute the
+        tool — the safe default for live-data and state-mutating tools.
+        """
+        # Recorded before any crew can offer its shared handler at kickoff,
+        # so copy() can distinguish a construction-time opt-in from runtime
+        # crew wiring (which must not turn copies into cachers).
+        self._constructor_cache_opt_in = bool(
+            self.cache
+            and (self.cache_handler is not None or "cache" in self.model_fields_set)
+        )
+        opted_in = self.cache_handler is not None or (
+            "cache" in self.model_fields_set and self.cache
+        )
+        if opted_in:
+            if not self.cache_handler:
+                self.cache_handler = CacheHandler()
+            self.set_cache_handler(self.cache_handler)
 
     def set_knowledge(self, crew_embedder: EmbedderConfig | None = None) -> None:
         """Initialize knowledge sources with the agent or crew embedder config."""
diff --git a/lib/crewai/src/crewai/agents/agent_builder/base_agent.py b/lib/crewai/src/crewai/agents/agent_builder/base_agent.py
index a12a4c18b..4530f9527 100644
--- a/lib/crewai/src/crewai/agents/agent_builder/base_agent.py
+++ b/lib/crewai/src/crewai/agents/agent_builder/base_agent.py
@@ -205,7 +205,11 @@ class BaseAgent(BaseModel, ABC, metaclass=AgentMeta):
         role (str): Role of the agent.
         goal (str): Objective of the agent.
         backstory (str): Backstory of the agent.
-        cache (bool): Whether the agent should use a cache for tool usage.
+        cache (bool): Whether the agent participates in tool-result caching
+            when a cache is enabled. The default (True) only permits
+            participation — caching activates when the crew sets cache=True
+            or the agent explicitly opts in with cache=True or a
+            cache_handler; cache=False excludes the agent entirely.
         config (dict[str, Any] | None): Configuration for the agent.
         verbose (bool): Verbose mode for the Agent Execution.
         max_rpm (int | None): Maximum number of requests per minute for the agent execution.
@@ -254,6 +258,7 @@ class BaseAgent(BaseModel, ABC, metaclass=AgentMeta):
     _logger: Logger = PrivateAttr(default_factory=lambda: Logger(verbose=False))
     _rpm_controller: RPMController | None = PrivateAttr(default=None)
     _request_within_rpm_limit: SerializableCallable | None = PrivateAttr(default=None)
+    _constructor_cache_opt_in: bool = PrivateAttr(default=False)
     _original_role: str | None = PrivateAttr(default=None)
     _original_goal: str | None = PrivateAttr(default=None)
     _original_backstory: str | None = PrivateAttr(default=None)
@@ -267,7 +272,14 @@ class BaseAgent(BaseModel, ABC, metaclass=AgentMeta):
         description="Configuration for the agent", default=None, exclude=True
     )
     cache: bool = Field(
-        default=True, description="Whether the agent should use a cache for tool usage."
+        default=True,
+        description=(
+            "Whether the agent participates in tool-result caching when a "
+            "cache is enabled. Caching itself is opt-in: it activates only "
+            "when the crew sets cache=True or the agent explicitly opts in "
+            "(cache=True or a cache_handler at construction). Set False to "
+            "exclude this agent even when the crew enables caching."
+        ),
     )
     verbose: bool = Field(
         default=False, description="Verbose mode for the Agent Execution"
@@ -716,6 +728,19 @@ class BaseAgent(BaseModel, ABC, metaclass=AgentMeta):
 
         copied_data = self.model_dump(exclude=exclude)
         copied_data = {k: v for k, v in copied_data.items() if v is not None}
+        # Tool-result caching distinguishes "explicitly enabled" from the
+        # field default via model_fields_set; don't let the dump turn the
+        # default into an explicit opt-in on the copy. An agent that opted
+        # in at construction via an explicit cache_handler (excluded from
+        # the dump) must stay opted in — carry the consent as cache=True so
+        # the copy wires its own fresh handler. A handler merely offered by
+        # a crew at kickoff is runtime wiring, not consent, and must not
+        # opt the copy in; _constructor_cache_opt_in is recorded before any
+        # crew wiring can happen.
+        if "cache" not in self.model_fields_set:
+            copied_data.pop("cache", None)
+            if self._constructor_cache_opt_in:
+                copied_data["cache"] = True
         return type(self)(
             **copied_data,
             llm=existing_llm,
diff --git a/lib/crewai/src/crewai/crew.py b/lib/crewai/src/crewai/crew.py
index 7d4a5107d..696d831c8 100644
--- a/lib/crewai/src/crewai/crew.py
+++ b/lib/crewai/src/crewai/crew.py
@@ -168,8 +168,11 @@ class Crew(FlowTrackable, BaseModel):
         manager_agent: Custom agent that will be used as manager.
         memory: Whether the crew should use memory to store memories of it's
             execution.
-        cache: Whether the crew should use a cache to store the results of the
-            tools execution.
+        cache: Whether to cache tool results for the crew's agents. Off by
+            default; when enabled, repeated calls to the same tool with
+            identical arguments reuse the first result without re-executing —
+            avoid enabling for live-data or state-mutating tools unless they
+            gate writes with a cache_function.
         function_calling_llm: The language model that will run the tool calling
             for all the agents.
         process: The process flow that the crew will follow (e.g., sequential,
@@ -216,7 +219,16 @@ class Crew(FlowTrackable, BaseModel):
     _kickoff_event_id: str | None = PrivateAttr(default=None)
 
     name: str | None = Field(default="crew")
-    cache: bool = Field(default=True)
+    cache: bool = Field(
+        default=False,
+        description=(
+            "Whether to cache tool results for the crew's agents. Opt-in: "
+            "when enabled, repeated calls to the same tool with identical "
+            "arguments return the first result without re-executing the "
+            "tool — do not enable for live-data or state-mutating tools "
+            "unless they set a cache_function that prevents caching."
+        ),
+    )
     tasks: list[Task] = Field(default_factory=list)
     agents: Annotated[
         list[BaseAgent],
@@ -1507,6 +1519,11 @@ class Crew(FlowTrackable, BaseModel):
             )
             self.manager_agent = manager
         manager.crew = self
+        # The manager is created outside the agents loop that offers the
+        # crew's cache handler at validation time; offer it here so an
+        # opted-in crew (cache=True) also dedupes the manager's tool calls.
+        if self.cache:
+            manager.set_cache_handler(self._cache_handler)
 
     def _get_execution_start_index(self, tasks: list[Task]) -> int | None:
         if self.checkpoint_kickoff_event_id is None:
diff --git a/lib/crewai/tests/test_crew.py b/lib/crewai/tests/test_crew.py
index 90d648711..0195112cb 100644
--- a/lib/crewai/tests/test_crew.py
+++ b/lib/crewai/tests/test_crew.py
@@ -859,6 +859,7 @@ def test_cache_hitting_between_agents(researcher, writer, ceo):
     crew = Crew(
         agents=[ceo, researcher],
         tasks=tasks,
+        cache=True,
     )
 
     with patch.object(CacheHandler, "read") as read:
@@ -2246,7 +2247,9 @@ def test_tools_with_custom_caching():
         agent=writer2,
     )
 
-    crew = Crew(agents=[writer1, writer2], tasks=[task1, task2, task3, task4])
+    crew = Crew(
+        agents=[writer1, writer2], tasks=[task1, task2, task3, task4], cache=True
+    )
 
     with patch.object(
         CacheHandler, "add", wraps=crew._cache_handler.add
diff --git a/lib/crewai/tests/test_tool_cache_default.py b/lib/crewai/tests/test_tool_cache_default.py
new file mode 100644
index 000000000..7a503d269
--- /dev/null
+++ b/lib/crewai/tests/test_tool_cache_default.py
@@ -0,0 +1,263 @@
+# mypy: ignore-errors
+"""Regression tests for EPD-180: tool-result caching used to be ON by default,
+so an LLM calling the same tool with identical arguments twice in one run got
+the first (possibly stale) result back without the tool executing — silently
+wrong for live-data tools, and silently dropped actions for stateful tools.
+
+Caching is now opt-in: ``Crew(cache=True)`` for crews, ``Agent(cache=True)``
+(or an explicit ``cache_handler``) for standalone agents. The machinery —
+including per-tool ``cache_function`` write gating — is unchanged once opted
+in.
+
+The end-to-end tests run fully offline: a fake OpenAI client scripts two
+identical tool calls followed by a final answer, mirroring the EPD-180
+clean-room repro.
+"""
+
+from openai.types.chat import ChatCompletion
+from pydantic import BaseModel, Field
+
+from crewai import LLM, Agent, Crew, Task
+from crewai.agents.cache.cache_handler import CacheHandler
+from crewai.tools import BaseTool
+
+
+class LookupArgs(BaseModel):
+    city: str = Field(description="City to look up.")
+
+
+def make_live_tool():
+    """A tool returning a different value on every real execution."""
+    executions = []
+
+    class LiveLookupTool(BaseTool):
+        name: str = "live_lookup"
+        description: str = "Returns a live (time-varying) reading for a city."
+        args_schema: type[BaseModel] = LookupArgs
+        # cache_function deliberately NOT set — exercising the default.
+
+        def _run(self, city: str) -> str:
+            executions.append(city)
+            return f"reading #{len(executions)} for {city}"
+
+    return LiveLookupTool(), executions
+
+
+def make_scripted_llm():
+    """An offline LLM whose client scripts two identical tool calls."""
+
+    def tool_call_response(call_id: str):
+        return {
+            "index": 0,
+            "finish_reason": "tool_calls",
+            "message": {
+                "role": "assistant",
+                "content": None,
+                "tool_calls": [
+                    {
+                        "id": call_id,
+                        "type": "function",
+                        "function": {
+                            "name": "live_lookup",
+                            "arguments": '{"city": "paris"}',
+                        },
+                    }
+                ],
+            },
+        }
+
+    scripted = [
+        tool_call_response("call_1"),
+        tool_call_response("call_2"),  # identical name+args, new id
+        {
+            "index": 0,
+            "finish_reason": "stop",
+            "message": {"role": "assistant", "content": "Final answer: done."},
+        },
+    ]
+
+    class FakeCompletions:
+        def __init__(self):
+            self.n = 0
+
+        def create(self, **params):
+            choice = scripted[min(self.n, len(scripted) - 1)]
+            self.n += 1
+            return ChatCompletion.model_validate(
+                {
+                    "id": f"chatcmpl-fake-{self.n}",
+                    "object": "chat.completion",
+                    "created": 1,
+                    "model": params.get("model", "gpt-4o"),
+                    "choices": [choice],
+                    "usage": {
+                        "prompt_tokens": 10,
+                        "completion_tokens": 5,
+                        "total_tokens": 15,
+                    },
+                }
+            )
+
+    class FakeClient:
+        def __init__(self):
+            self.chat = type("Chat", (), {"completions": FakeCompletions()})()
+
+    llm = LLM(model="openai/gpt-4o")
+    llm._client = FakeClient()
+    return llm
+
+
+def run_crew(**crew_kwargs):
+    tool, executions = make_live_tool()
+    agent = Agent(
+        role="reader",
+        goal="Look things up.",
+        backstory="Test agent.",
+        llm=make_scripted_llm(),
+        tools=[tool],
+        verbose=False,
+    )
+    task = Task(
+        description="Look up paris twice and report.",
+        expected_output="A report.",
+        agent=agent,
+    )
+    crew = Crew(agents=[agent], tasks=[task], verbose=False, **crew_kwargs)
+    crew.kickoff()
+    return executions
+
+
+class TestToolCachingIsOptIn:
+    def test_default_reexecutes_identical_tool_calls(self):
+        """EPD-180: with no opt-in, both identical calls must really execute."""
+        executions = run_crew()
+        assert len(executions) == 2
+
+    def test_crew_cache_true_dedupes_identical_tool_calls(self):
+        """Opting in via Crew(cache=True) restores the dedup behavior."""
+        executions = run_crew(cache=True)
+        assert len(executions) == 1
+
+
+class TestAgentCacheWiring:
+    def _agent(self, **kwargs) -> Agent:
+        return Agent(
+            role="reader",
+            goal="Look things up.",
+            backstory="Test agent.",
+            **kwargs,
+        )
+
+    def test_standalone_agent_has_no_cache_by_default(self):
+        agent = self._agent()
+        assert agent.tools_handler.cache is None
+        assert agent.cache_handler is None
+
+    def test_standalone_agent_explicit_cache_true_opts_in(self):
+        agent = self._agent(cache=True)
+        assert agent.tools_handler.cache is not None
+        assert agent.cache_handler is not None
+
+    def test_standalone_agent_explicit_cache_handler_opts_in(self):
+        handler = CacheHandler()
+        agent = self._agent(cache_handler=handler)
+        assert agent.tools_handler.cache is handler
+
+    def test_explicit_cache_false_stays_off_even_with_handler(self):
+        agent = self._agent(cache=False, cache_handler=CacheHandler())
+        assert agent.tools_handler.cache is None
+
+    def test_agents_accept_a_crew_offered_handler_by_default(self):
+        """``Crew(cache=True)`` offers its handler via set_cache_handler at
+        kickoff; agents that didn't explicitly opt out must accept it."""
+        agent = self._agent()
+        assert agent.tools_handler.cache is None
+
+        handler = CacheHandler()
+        agent.set_cache_handler(handler)
+        assert agent.tools_handler.cache is handler
+
+    def test_agents_that_opted_out_refuse_a_crew_offered_handler(self):
+        agent = self._agent(cache=False)
+        agent.set_cache_handler(CacheHandler())
+        assert agent.tools_handler.cache is None
+
+    def test_copy_of_default_agent_does_not_opt_in(self):
+        """copy() rebuilds from model_dump(), which includes the field
+        default cache=True — that must not read as an explicit opt-in on
+        the copy (Bugbot review finding on the original PR)."""
+        copied = self._agent().copy()
+        assert copied.tools_handler.cache is None
+        assert copied.cache_handler is None
+
+    def test_copy_of_opted_in_agent_stays_opted_in(self):
+        copied = self._agent(cache=True).copy()
+        assert copied.tools_handler.cache is not None
+
+    def test_copy_of_handler_opted_in_agent_stays_opted_in(self):
+        """An explicit cache_handler is an opt-in too; copy() excludes the
+        handler itself, but the consent must survive — the copy wires its
+        own fresh handler (Bugbot review finding on the original PR)."""
+        source = self._agent(cache_handler=CacheHandler())
+        copied = source.copy()
+        assert copied.tools_handler.cache is not None
+        assert copied.tools_handler.cache is not source.tools_handler.cache
+
+    def test_copy_of_explicit_cache_false_with_handler_stays_off(self):
+        copied = self._agent(cache=False, cache_handler=CacheHandler()).copy()
+        assert copied.tools_handler.cache is None
+
+    def test_copy_of_crew_wired_agent_does_not_opt_in(self):
+        """A handler offered by a crew at kickoff (set_cache_handler) is
+        runtime wiring, not construction-time consent — copies of such
+        agents must not become standalone cachers (Bugbot review finding
+        on the original PR)."""
+        agent = self._agent()
+        agent.set_cache_handler(CacheHandler())  # what Crew(cache=True) does
+        assert agent.tools_handler.cache is not None
+
+        copied = agent.copy()
+        assert copied.tools_handler.cache is None
+        assert copied.cache_handler is None
+
+
+class TestHierarchicalManagerCacheWiring:
+    """The auto-created hierarchical manager is built outside the agents
+    loop that offers the crew's cache handler; an opted-in crew must wire
+    the manager too (Bugbot review finding on the original PR)."""
+
+    def _crew(self, **crew_kwargs) -> Crew:
+        from crewai.process import Process
+
+        agent = Agent(role="worker", goal="Do work.", backstory="Test agent.")
+        task = Task(description="Do the work.", expected_output="Done.")
+        return Crew(
+            agents=[agent],
+            tasks=[task],
+            process=Process.hierarchical,
+            manager_llm="gpt-4o",
+            **crew_kwargs,
+        )
+
+    def test_manager_gets_crew_handler_when_cache_enabled(self):
+        crew = self._crew(cache=True)
+        crew._create_manager_agent()
+        assert crew.manager_agent.tools_handler.cache is crew._cache_handler
+
+    def test_manager_has_no_cache_when_crew_did_not_opt_in(self):
+        crew = self._crew()
+        crew._create_manager_agent()
+        assert crew.manager_agent.tools_handler.cache is None
+
+    def test_user_provided_manager_with_cache_false_stays_excluded(self):
+        manager = Agent(
+            role="manager",
+            goal="Manage.",
+            backstory="Test manager.",
+            cache=False,
+            allow_delegation=True,
+        )
+        crew = self._crew(cache=True)
+        crew.manager_agent = manager
+        crew._create_manager_agent()
+        assert manager.tools_handler.cache is None