diff --git a/e2e-tests/test_hooks.py b/e2e-tests/test_hooks.py
index a01b65c..fda60e9 100644
--- a/e2e-tests/test_hooks.py
+++ b/e2e-tests/test_hooks.py
@@ -6,6 +6,7 @@ from claude_agent_sdk import (
     ClaudeAgentOptions,
     ClaudeSDKClient,
     HookContext,
+    HookInput,
     HookJSONOutput,
     HookMatcher,
 )
@@ -18,7 +19,7 @@ async def test_hook_with_permission_decision_and_reason():
     hook_invocations = []
 
     async def test_hook(
-        input_data: dict, tool_use_id: str | None, context: HookContext
+        input_data: HookInput, tool_use_id: str | None, context: HookContext
     ) -> HookJSONOutput:
         """Hook that uses permissionDecision and reason fields."""
         tool_name = input_data.get("tool_name", "")
@@ -73,7 +74,7 @@ async def test_hook_with_continue_and_stop_reason():
     hook_invocations = []
 
     async def post_tool_hook(
-        input_data: dict, tool_use_id: str | None, context: HookContext
+        input_data: HookInput, tool_use_id: str | None, context: HookContext
     ) -> HookJSONOutput:
         """PostToolUse hook that stops execution with stopReason."""
         tool_name = input_data.get("tool_name", "")
@@ -114,7 +115,7 @@ async def test_hook_with_additional_context():
     hook_invocations = []
 
     async def context_hook(
-        input_data: dict, tool_use_id: str | None, context: HookContext
+        input_data: HookInput, tool_use_id: str | None, context: HookContext
     ) -> HookJSONOutput:
         """Hook that provides additional context."""
         hook_invocations.append("context_added")
diff --git a/examples/hooks.py b/examples/hooks.py
index e533ac7..a8001d4 100644
--- a/examples/hooks.py
+++ b/examples/hooks.py
@@ -19,6 +19,7 @@ from claude_agent_sdk import ClaudeAgentOptions, ClaudeSDKClient
 from claude_agent_sdk.types import (
     AssistantMessage,
     HookContext,
+    HookInput,
     HookJSONOutput,
     HookMatcher,
     Message,
@@ -43,7 +44,7 @@ def display_message(msg: Message) -> None:
 
 ##### Hook callback functions
 async def check_bash_command(
-    input_data: dict[str, Any], tool_use_id: str | None, context: HookContext
+    input_data: HookInput, tool_use_id: str | None, context: HookContext
 ) -> HookJSONOutput:
     """Prevent certain bash commands from being executed."""
     tool_name = input_data["tool_name"]
@@ -70,7 +71,7 @@ async def check_bash_command(
 
 
 async def add_custom_instructions(
-    input_data: dict[str, Any], tool_use_id: str | None, context: HookContext
+    input_data: HookInput, tool_use_id: str | None, context: HookContext
 ) -> HookJSONOutput:
     """Add custom instructions when a session starts."""
     return {
@@ -82,7 +83,7 @@ async def add_custom_instructions(
 
 
 async def review_tool_output(
-    input_data: dict[str, Any], tool_use_id: str | None, context: HookContext
+    input_data: HookInput, tool_use_id: str | None, context: HookContext
 ) -> HookJSONOutput:
     """Review tool output and provide additional context or warnings."""
     tool_response = input_data.get("tool_response", "")
@@ -102,7 +103,7 @@ async def review_tool_output(
 
 
 async def strict_approval_hook(
-    input_data: dict[str, Any], tool_use_id: str | None, context: HookContext
+    input_data: HookInput, tool_use_id: str | None, context: HookContext
 ) -> HookJSONOutput:
     """Demonstrates using permissionDecision to control tool execution."""
     tool_name = input_data.get("tool_name")
@@ -135,7 +136,7 @@ async def strict_approval_hook(
 
 
 async def stop_on_error_hook(
-    input_data: dict[str, Any], tool_use_id: str | None, context: HookContext
+    input_data: HookInput, tool_use_id: str | None, context: HookContext
 ) -> HookJSONOutput:
     """Demonstrates using continue=False to stop execution on certain conditions."""
     tool_response = input_data.get("tool_response", "")
diff --git a/src/claude_agent_sdk/__init__.py b/src/claude_agent_sdk/__init__.py
index 45eccec..6c44747 100644
--- a/src/claude_agent_sdk/__init__.py
+++ b/src/claude_agent_sdk/__init__.py
@@ -18,11 +18,13 @@ from .query import query
 from .types import (
     AgentDefinition,
     AssistantMessage,
+    BaseHookInput,
     CanUseTool,
     ClaudeAgentOptions,
     ContentBlock,
     HookCallback,
     HookContext,
+    HookInput,
     HookJSONOutput,
     HookMatcher,
     McpSdkServerConfig,
@@ -33,8 +35,13 @@ from .types import (
     PermissionResultAllow,
     PermissionResultDeny,
     PermissionUpdate,
+    PostToolUseHookInput,
+    PreCompactHookInput,
+    PreToolUseHookInput,
     ResultMessage,
     SettingSource,
+    StopHookInput,
+    SubagentStopHookInput,
     SystemMessage,
     TextBlock,
     ThinkingBlock,
@@ -42,6 +49,7 @@ from .types import (
     ToolResultBlock,
     ToolUseBlock,
     UserMessage,
+    UserPromptSubmitHookInput,
 )
 
 # MCP Server Support
@@ -307,8 +315,17 @@ __all__ = [
     "PermissionResultAllow",
     "PermissionResultDeny",
     "PermissionUpdate",
+    # Hook support
     "HookCallback",
     "HookContext",
+    "HookInput",
+    "BaseHookInput",
+    "PreToolUseHookInput",
+    "PostToolUseHookInput",
+    "UserPromptSubmitHookInput",
+    "StopHookInput",
+    "SubagentStopHookInput",
+    "PreCompactHookInput",
     "HookJSONOutput",
     "HookMatcher",
     # Agent support
diff --git a/src/claude_agent_sdk/types.py b/src/claude_agent_sdk/types.py
index 3095dfd..82a57ad 100644
--- a/src/claude_agent_sdk/types.py
+++ b/src/claude_agent_sdk/types.py
@@ -157,6 +157,73 @@ HookEvent = (
 )
 
 
+# Hook input types - strongly typed for each hook event
+class BaseHookInput(TypedDict):
+    """Base hook input fields present across many hook events."""
+
+    session_id: str
+    transcript_path: str
+    cwd: str
+    permission_mode: NotRequired[str]
+
+
+class PreToolUseHookInput(BaseHookInput):
+    """Input data for PreToolUse hook events."""
+
+    hook_event_name: Literal["PreToolUse"]
+    tool_name: str
+    tool_input: dict[str, Any]
+
+
+class PostToolUseHookInput(BaseHookInput):
+    """Input data for PostToolUse hook events."""
+
+    hook_event_name: Literal["PostToolUse"]
+    tool_name: str
+    tool_input: dict[str, Any]
+    tool_response: Any
+
+
+class UserPromptSubmitHookInput(BaseHookInput):
+    """Input data for UserPromptSubmit hook events."""
+
+    hook_event_name: Literal["UserPromptSubmit"]
+    prompt: str
+
+
+class StopHookInput(BaseHookInput):
+    """Input data for Stop hook events."""
+
+    hook_event_name: Literal["Stop"]
+    stop_hook_active: bool
+
+
+class SubagentStopHookInput(BaseHookInput):
+    """Input data for SubagentStop hook events."""
+
+    hook_event_name: Literal["SubagentStop"]
+    stop_hook_active: bool
+
+
+class PreCompactHookInput(BaseHookInput):
+    """Input data for PreCompact hook events."""
+
+    hook_event_name: Literal["PreCompact"]
+    trigger: Literal["manual", "auto"]
+    custom_instructions: str | None
+
+
+# Union type for all hook inputs
+HookInput = (
+    PreToolUseHookInput
+    | PostToolUseHookInput
+    | UserPromptSubmitHookInput
+    | StopHookInput
+    | SubagentStopHookInput
+    | PreCompactHookInput
+)
+
+
 # Hook-specific output types
 class PreToolUseHookSpecificOutput(TypedDict):
     """Hook-specific output for PreToolUse events."""
@@ -265,21 +332,22 @@ class SyncHookJSONOutput(TypedDict):
 HookJSONOutput = AsyncHookJSONOutput | SyncHookJSONOutput
 
 
-@dataclass
-class HookContext:
-    """Context information for hook callbacks."""
+class HookContext(TypedDict):
+    """Context information for hook callbacks.
 
-    signal: Any | None = None  # Future: abort signal support
+    Fields:
+        signal: Reserved for future abort signal support. Currently always None.
+    """
+
+    signal: Any | None  # Future: abort signal support
 
 
 HookCallback = Callable[
     # HookCallback input parameters:
-    # - input
-    #   See https://docs.anthropic.com/en/docs/claude-code/hooks#hook-input for
-    #   the type of 'input', the first value.
-    # - tool_use_id
-    # - context
-    [dict[str, Any], str | None, HookContext],
+    # - input: Strongly-typed hook input with discriminated unions based on hook_event_name
+    # - tool_use_id: Optional tool use identifier
+    # - context: Hook context with abort signal support (currently placeholder)
+    [HookInput, str | None, HookContext],
     Awaitable[HookJSONOutput],
 ]
 
diff --git a/tests/test_tool_callbacks.py b/tests/test_tool_callbacks.py
index 4987ede..8ace3c8 100644
--- a/tests/test_tool_callbacks.py
+++ b/tests/test_tool_callbacks.py
@@ -7,6 +7,7 @@ import pytest
 from claude_agent_sdk import (
     ClaudeAgentOptions,
     HookContext,
+    HookInput,
     HookJSONOutput,
     HookMatcher,
     PermissionResultAllow,
@@ -216,7 +217,7 @@ class TestHookCallbacks:
         hook_calls = []
 
         async def test_hook(
-            input_data: dict, tool_use_id: str | None, context: HookContext
+            input_data: HookInput, tool_use_id: str | None, context: HookContext
         ) -> dict:
             hook_calls.append({"input": input_data, "tool_use_id": tool_use_id})
             return {"processed": True}
@@ -266,7 +267,7 @@ class TestHookCallbacks:
 
         # Test all SyncHookJSONOutput fields together
         async def comprehensive_hook(
-            input_data: dict, tool_use_id: str | None, context: HookContext
+            input_data: HookInput, tool_use_id: str | None, context: HookContext
         ) -> HookJSONOutput:
             return {
                 # Control fields
@@ -349,7 +350,7 @@ class TestHookCallbacks:
         """Test AsyncHookJSONOutput type with proper async fields."""
 
         async def async_hook(
-            input_data: dict, tool_use_id: str | None, context: HookContext
+            input_data: HookInput, tool_use_id: str | None, context: HookContext
         ) -> HookJSONOutput:
             # Test that async hooks properly use async_ and asyncTimeout fields
             return {
@@ -399,7 +400,7 @@ class TestHookCallbacks:
         """Test that Python-safe field names (async_, continue_) are converted to CLI format (async, continue)."""
 
         async def conversion_test_hook(
-            input_data: dict, tool_use_id: str | None, context: HookContext
+            input_data: HookInput, tool_use_id: str | None, context: HookContext
         ) -> HookJSONOutput:
             # Return both async_ and continue_ to test conversion
             return {
@@ -468,7 +469,7 @@ class TestClaudeAgentOptionsIntegration:
             return PermissionResultAllow()
 
         async def my_hook(
-            input_data: dict, tool_use_id: str | None, context: HookContext
+            input_data: HookInput, tool_use_id: str | None, context: HookContext
         ) -> dict:
             return {}